Keto Apple Cinnamon Cake
A classic apple cake clocks in at around 45 g of carbs per slice once you add up wheat flour, sugar and 800 g of apples. This keto version cuts apples down to 150 g (spread across 12 slices = 12.5 g per slice) and swaps flour and sugar for almond flour and erythritol. The result: 5 g of net carbs per slice with the full apple and cinnamon flavor. Thin apple slices on top look impressive without sending the carb count through the roof. Apples are higher in carbs than typical keto fruits, so portion control matters; the trick here is using a small amount of tart apple as a topping rather than mixing large quantities into the batter.
Key facts at a glance
- Prep time: approx. 15 minutes active, 45 minutes baking, makes 12 slices.
- Approx. 5 g net carbs and 22 g fat per slice.
- Ingredients: almond flour, eggs, butter, erythritol, 1 small apple (150 g), cinnamon, vanilla.
- Great for a coffee break or as a fall cake, keeps 4 days, freezer-friendly.
Ingredients
The recipe makes 12 slices from a 22 cm springform pan. One coffee-break portion is 1 slice (approx. 80 g).
| Amount | Ingredient | Note | ||
|---|---|---|---|---|
| Almond flour (blanched) | - | |||
| Eggs (medium, room temperature) | - | |||
| Butter (soft) | - | |||
| Erythritol | - | |||
| Tart apple (Bramley or similar) | 1 small apple | |||
| 1 small apple | ||||
| Cinnamon | for the batter | |||
| for the batter | ||||
| Cinnamon | for the apple topping | |||
| for the apple topping | ||||
| Erythritol | for the apple topping | |||
| for the apple topping | ||||
| Vanilla extract | approx. 2 tsp | |||
| approx. 2 tsp | ||||
| Lemon juice | approx. 1 tsp; to keep apple slices from browning | |||
| approx. 1 tsp; to keep apple slices from browning | ||||
| Baking powder | - | |||
| Salt | - | |||
Preparation
-
Prep oven and pan
approx. 5 minutes180 g Butter (soft) 150 g Tart apple (Bramley or similar) 1 small apple 5 ml Lemon juice approx. 1 tsp; to keep apple slices from browning Preheat the oven to 175 C (350 F), conventional heat. Line a 22 cm springform pan with parchment paper and butter the sides. Peel and core the apple (150 g) and slice it into 2 to 3 mm thin pieces. Sprinkle with lemon juice (1 tsp) to keep it from browning.
-
Make the batter
approx. 8 minutes300 g Almond flour (blanched) 5 piece Eggs (medium, room temperature) 100 g Erythritol 3 tsp Cinnamon for the batter 1 tsp Cinnamon for the apple topping 20 g Erythritol for the apple topping 10 ml Vanilla extract approx. 2 tsp 2 tsp Baking powder 1 pinch Salt Beat the soft butter (180 g) and erythritol (100 g) with a hand mixer for 3 minutes until fluffy. Beat in the eggs (5) one at a time, allowing 30 seconds per egg. Add vanilla (2 tsp). Fold in almond flour (300 g), baking powder (2 tsp), cinnamon (3 tsp) and salt.
-
Top the cake
approx. 5 minutesTransfer the batter to the springform pan and smooth it with a spatula. Arrange the apple slices in a spiral from the outside in, pressing them gently into the batter. A dense pattern looks generous even though the apple amount is small.
-
Bake
approx. 45 minutesBake on the middle rack for 30 minutes. Mix cinnamon (1 tsp) with erythritol (20 g) and sprinkle over the apple surface. Important: only after 30 minutes, otherwise the cinnamon will burn. Bake for another 15 minutes; check with a skewer in the center (between apple slices): moist crumbs mean it's done.
-
Cool and serve
approx. 45 minutes (resting)Take the pan out of the oven and let it rest for 15 minutes. Carefully release the springform ring and let the cake cool on a wire rack for another 30 minutes. Best served lukewarm with a dollop of mascarpone or whipped cream. Cut into 12 equal slices.
You did it! Enjoy every delicious bite.
Tips for a perfect keto apple cake
- Choose tart apple varieties (Bramley, Granny Smith), less sweetness, fewer carbs and a more intense apple flavor.
- Slice the apples thin (2 to 3 mm), they distribute better and caramelize more beautifully during baking.
- Slice the apple just before topping, otherwise it browns. A few drops of lemon juice prevent browning.
- Line the springform pan with parchment, apple juice will run out and can stick to the sides.
- Add the cinnamon-erythritol topping only after 30 minutes of baking, otherwise the cinnamon will burn.
Why this apple cake fits a keto diet
Apples have around 11 g of net carbs per 100 g, so 800 g for a classic apple cake adds up quickly. The key to this keto apple cake: drastically reducing the apple amount to just 150 g (1 small apple) and spreading it across 12 slices. That works out to only 12.5 g of apple per slice = 1.4 g of net carbs. Combined with almond flour (1 g per slice) and cinnamon (0.1 g), you land at the 5 g of net carbs. Important: thin apple slices on top instead of folded into the batter. That looks generous, intensifies the flavor through caramelization, and keeps the portion under control. Cinnamon reinforces the apple notes and has additional blood-sugar-stabilizing effects.
Source: USDA FoodData Central - Apples, raw, with skin , PubMed - Cinnamon and glucose control
Are apples keto-friendly?
Apples are the borderline fruit: at 11 g of net carbs per 100 g, they sit higher than berries (5 to 7 g) but lower than bananas (20 g). In small portions (15 to 25 g per serving) they fit into keto. Rule of thumb: a quarter of an apple per person, not a whole one. Tart varieties (Bramley, Granny Smith) are lower in carbs than sweet ones (Gala, Fuji). For this recipe: 1 small Bramley or Granny Smith of approx. 150 g.
Why cinnamon is the secret star
Cinnamon (preferably Ceylon) doesn't just boost the apple aroma, it has shown blood-sugar-stabilizing effects in studies. A meta-analysis in the Journal of Medicinal Food (2010) found significant reductions in fasting blood glucose with regular intake of 1 to 6 g of cinnamon per day. For the cake: 3 tsp of cinnamon in the batter plus 1 tsp of cinnamon-erythritol mix on top. Cassia cinnamon contains coumarin, with a maximum of 2 g per day considered safe; Ceylon is the safer choice for regular use.
How to serve and vary the apple cake
The cake is at its best served warm with a dollop of mascarpone or unsweetened whipped cream. From personal experience: the apple flavor is even more intense the next day, once the cinnamon and apple have had time to mingle. In fall, pairing it with a cinnamon and star anise tea turns it into a real afternoon highlight. For a classic touch: a quick vanilla sauce made from mascarpone, cream and vanilla on the side.
Meal prep: storage and freezing
Keeps 2 days at room temperature and up to 4 days wrapped in the fridge. Freezing: the whole cake or individual slices keep for up to 2 months. Thaw overnight in the fridge or for 30 seconds in the microwave. Tip: warm briefly in the oven at 150 C (300 F) for 5 minutes before serving, then it tastes freshly baked.
Variations: streusel, nuts, pear
Streusel version: knead 50 g almond flour with 30 g cold butter, 20 g erythritol and 1 tsp cinnamon into crumbles and scatter over the batter before baking, adds approx. 0.5 g of carbs per slice. Nut version: fold 50 g of roughly chopped walnuts into the batter for more crunch, adds approx. 0.5 g of carbs. Pear version: swap the apple for 150 g of pear (slightly sweeter, 9 g carbs per 100 g). Spiced version: 1 tsp of mixed gingerbread spice instead of plain cinnamon for a wintery note.
Nutrition values
| Nutrient | Per 100 g | Per slice (approx. 80 g) | Keto context |
|---|---|---|---|
| Calories | approx. 350 kcal | approx. 280 kcal | Filling; main energy from butter and almond flour. |
| Filling; main energy from butter and almond flour. | |||
| Fat | approx. 28 g | approx. 22 g | Saturated from butter, unsaturated from almond flour. |
| Saturated from butter, unsaturated from almond flour. | |||
| Net carbs | approx. 6 g | approx. 5 g | Slightly higher than other keto cakes due to apple, still keto-friendly. |
| Slightly higher than other keto cakes due to apple, still keto-friendly. | |||
| Sugar | approx. 2.8 g | approx. 2.2 g | Natural sugar from apple; no added sugar, erythritol doesn't count. |
| Natural sugar from apple; no added sugar, erythritol doesn't count. | |||
| Protein | approx. 7.5 g | approx. 6 g | Moderate; eggs and almond flour provide quality protein. |
| Moderate; eggs and almond flour provide quality protein. | |||
| Salt | approx. 0.2 g | approx. 0.15 g | Low; pinch of salt and baking powder. |
| Low; pinch of salt and baking powder. | |||
Note: Nutrition values are estimated averages per 100 g and per serving and may vary depending on ingredients, brands, portion size, and preparation. They do not replace individual nutrition or medical advice.
FAQ
5 g of net carbs is a bit more than other keto cakes, does it still fit keto?
Yes. With a daily limit of 20 to 50 g of carbs, 1 slice (5 g) is easy to fit in. Apple is the borderline fruit, so apple cakes tend to land at the higher end. For strict keto under 20 g per day: take half a slice or reduce the apple amount further (to 100 g).
Can I use more apples?
You can, but the carbs scale proportionally: 300 g of apples adds approx. 1.7 g of carbs per slice (around 7 g total), 500 g adds approx. 4 g per slice (around 9 g total). For a classic look with dense apple coverage, stay at 200 g, which is still defensible on keto (6 g of carbs per slice).
Which apple variety works best?
Tart varieties are more keto-friendly and taste more intense. Bramley: approx. 10 g of carbs per 100 g, very tart. Granny Smith: approx. 9 g of carbs per 100 g, crisp and sour. Cox's Orange Pippin: approx. 11 g of carbs per 100 g, balanced. Avoid sweet varieties like Gala, Fuji or Pink Lady (13 to 14 g of carbs per 100 g), they make the cake unnecessarily sugary.
How long does the cake keep with apple in it?
2 days at room temperature, up to 4 days wrapped in the fridge. In the freezer 2 months, the apple pieces get slightly softer on thawing but the flavor stays excellent. Tip: freeze individual slices wrapped in foil, then thaw one as needed and reheat in the microwave.