Keto Lemon Cake with Glaze
A classic lemon cake made with wheat flour and a powdered-sugar glaze comes in at around 38 g of carbs per slice. This keto version with almond flour and erythritol stays at 3 g net carbs, glaze included. Fresh zest from two organic lemons and lemon juice in the batter deliver the signature bright, tangy note, while the glaze of powdered erythritol and lemon juice creates the white, slightly translucent coating you know from the original.
Key facts at a glance
- Prep time: approx. 15 minutes active, 40 minutes baking + 30 minutes glazing, makes 12 slices.
- Approx. 3 g net carbs and 22 g fat per slice (glaze included).
- Ingredients: almond flour, eggs, butter, erythritol, organic lemons, cream, baking powder, vanilla.
- Great with coffee or as a summer cake, keeps for 4 days and freezes well.
Ingredients
The recipe makes 12 slices from a 25 cm loaf pan. A serving with coffee is 1 slice (approx. 75 g).
| Amount | Ingredient | Note | ||
|---|---|---|---|---|
| Almond flour (blanched) | - | |||
| Eggs (medium, room temperature) | - | |||
| Butter (softened) | - | |||
| Erythritol (powdered) | - | |||
| Organic lemons | zest of both + 50 ml juice | |||
| zest of both + 50 ml juice | ||||
| Cream (30%) | - | |||
| Vanilla extract | approx. 2 tsp | |||
| approx. 2 tsp | ||||
| Baking powder | - | |||
| Salt | - | |||
| Erythritol (powdered) | for the glaze | |||
| for the glaze | ||||
| Lemon juice | approx. 1 tbsp; for the glaze | |||
| approx. 1 tbsp; for the glaze | ||||
Preparation
Cream butter with erythritol, then beat in the eggs one at a time. Add lemon zest, lemon juice and cream, then fold in almond flour and baking powder. Bake at 170 °C (338 °F) for 40 minutes. Stir together a glaze from powdered erythritol and lemon juice, then pour it over the cooled cake.
Why this lemon cake fits keto
Lemons are the most keto-friendly citrus fruit: 50 g of juice contains only 1 g of carbs, plus vitamin C and that bright fresh flavor. The zest carries the essential oil and therefore the most intense lemon aroma, with no carbs. Almond flour replaces wheat (5 g vs. 70 g net carbs per 100 g), and erythritol replaces sugar. The glaze is usually the sugar trap on a lemon cake (a classic powdered-sugar glaze adds about 25 g of sugar per cake); with powdered erythritol it stays carb-free. The total: approx. 3 g net carbs and 22 g fat per slice, including the white, intensely lemony glaze topping.
Source: USDA FoodData Central – Lemon juice, raw
Why organic lemon zest is the key
The essential oil in lemon peel is more intense than the juice; one gram of zest carries about the aromatic depth of 15 ml of juice. Important: only grate the yellow layer, not the white pith (which is bitter). Organic lemons are a must, because conventional lemons are often treated with peel preservatives (E 230, E 231, imazalil). Rule of thumb: 1 tsp of zest per lemon. This recipe uses 2 organic lemons for a strong flavor.
How the glaze works without powdered sugar
Powdered erythritol (Sukrin Icing, or ground yourself in a coffee grinder) behaves almost like powdered sugar when mixed with liquid. Rule of thumb: 60 g of powdered erythritol + 15 ml of lemon juice gives a spreadable, slightly thick glaze. Too runny? Add more erythritol. Too stiff? Add 1 tsp of water. Important: pour the glaze only over a fully cooled cake. On a warm cake it turns milky and runs straight off.
How do I serve and vary the lemon cake?
The lemon cake is at its best fresh. The glaze is fully set after 2 hours and the cake slices cleanly. From experience: 2 organic lemons really are enough for a strong flavor, more makes the cake sour. Optionally garnish with a few fresh berries or mint leaves. In summer it pairs perfectly with a glass of iced tea made from organic lemons for an afternoon dessert.
Meal prep: storage and freezing
At room temperature under a cake dome it keeps for 2 days. In the fridge, wrapped in foil, up to 4 days. Freezing: best to freeze WITHOUT the glaze (the glaze turns grainy when thawed). After thawing, mix up a fresh glaze and apply it. Freezing individual slices is handy for one-person households: just grab a slice and thaw it.
Variations: poppy seed, blueberry, lime
Lemon poppy seed: stir 30 g of poppy seeds into the batter, the classic lemon poppy seed cake, +0.5 g carbs per slice. Lemon blueberry: 80 g of fresh blueberries in the batter (coat in flour so they don't sink), +0.7 g carbs. Lime version: 2 organic limes instead of lemons, more tropical and slightly more bitter. Lavender twist: 1 tsp of dried lavender flowers in the batter, very aromatic and Mediterranean.
Which tips help with keto lemon cake?
- Wash the lemons in warm water and dry them before zesting, this removes residual wax and dirt.
- Grate only the yellow layer (not the white pith), otherwise the cake turns bitter.
- Bring the eggs to room temperature, cold eggs make the butter seize up again.
- Pour the glaze only over a fully cooled cake, otherwise it runs straight off.
- If you don't have powdered erythritol on hand, blitz erythritol in a coffee grinder, otherwise the glaze stays grainy.
Nutrition values
| Nutrient | Per 100 g | Per slice (approx. 75 g) | Keto context |
|---|---|---|---|
| Calories | approx. 370 kcal | approx. 275 kcal | Filling; main energy from butter and almond flour. |
| Filling; main energy from butter and almond flour. | |||
| Fat | approx. 29 g | approx. 22 g | Saturated from butter, unsaturated from almond flour, a classic keto profile. |
| Saturated from butter, unsaturated from almond flour, a classic keto profile. | |||
| Net carbs | approx. 4 g | approx. 3 g | Low for a glazed cake; almond flour is the main source, lemon is negligible. |
| Low for a glazed cake; almond flour is the main source, lemon is negligible. | |||
| Sugar | approx. 0.8 g | approx. 0.6 g | Natural sugar from lemon juice and almond flour; no added sugar. |
| Natural sugar from lemon juice and almond flour; no added sugar. | |||
| Protein | approx. 8 g | approx. 6 g | Moderate; eggs and almond flour deliver high-quality protein. |
| Moderate; eggs and almond flour deliver high-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
Can I use bottled lemon juice?
In the batter it works in a pinch (make sure it is 100% lemon juice with no added sugar, not a sweetened lemon drink). For the glaze and the aroma, fresh juice plus zest is clearly better, the essential oil in the peel accounts for about 60% of the lemon aroma. With bottled juice the cake tastes flatter.
Why is my glaze grainy?
The erythritol probably isn't ground finely enough. Fix: grind erythritol in a coffee grinder or blender until it looks like powdered sugar. Alternatively buy Sukrin Icing (ready-powdered erythritol). Another cause: glaze applied to a warm cake, since erythritol recrystallizes as it cools quickly.
Can you taste the almond flour?
In a lemon cake the nutty almond-flour undertone is well covered by the lemon. In my experience it's less noticeable than in vanilla or cream cakes, but more than in chocolate cakes. Tip: use zest from 2 lemons instead of one, that boosts the lemon aroma and covers the almond note better.
How long does the glazed cake keep?
At room temperature under a cake dome 2 days, in the fridge wrapped in foil up to 4 days. The glaze sets fully after 2 hours and stays firm. Freezing: best WITHOUT the glaze (it turns grainy on thawing); after thawing, glaze it fresh, which takes just 5 minutes and looks perfect again.