1g Net Carbs
This low carb Texas sheet cake, built with a bright lemon glaze, earns its reputation from the method, not the size of the pan. Butter, water, and citrus come to a boil, get poured straight over the dry mix, and the cake bakes thin and fast while a warm glaze goes on before it ever cools. That method is exactly why this low carb lemon sheet cake works. The hot liquid hydrates Carbquik and almond flour in a way creamed butter never does, and the result is a moist, tender crumb instead of the dry, sandy texture that sinks most grain-free cakes. For another low carb dessert built the same honest way, see the crustless pumpkin pie.
Table of Contents
Why This Low Carb Texas Sheet Cake Holds Together
Carbquik supplies the structure and the wheat-like chew. Almond flour supplies fat and moisture so the crumb stays soft for days. Sour cream adds tang and tenderness at almost no carb cost, and three eggs bind the whole thin slab so squares lift clean out of the pan. Nothing here is pretending to be something else — it bakes, slices, and eats like a real sheet cake.
Sweetener Strategy
Per IFIC guidance, allulose does most of the lifting because it dissolves completely, stays soft, and never recrystallizes into grit as the cake cools. But allulose alone runs about 70% as sweet as sugar, and a cake carrying this much lemon acid needs real sweetness to push back. A small measure of monk fruit erythritol blend closes that gap. Kept to a minority share and paired with allulose, it sharpens sweetness without turning the glaze sandy the next day.
- Granular sweeteners in the batter, powdered sweeteners in the glaze — no exceptions
- Allulose stays the majority in both, especially the glaze
- Bake at 325°F, since allulose browns faster than sugar
Ingredient Spotlight
Fresh lemon is the entire point. Two to three lemons yield the juice and zest this cake needs, and bottled juice bakes out flat and slightly bitter every time. Zest goes into both the batter and the glaze, because the oils in the peel carry aroma that juice alone cannot.
Glaze Technique
The glaze goes on while the cake is still hot from the oven. Warm cake absorbs the top layer instead of letting it sit on the surface as a separate lid, and that soaked, glossy top is the Texas sheet cake signature. An offset spatula spreads it to the edges in about thirty seconds. It sets soft rather than hard — that is correct, and it is exactly what the allulose is doing its job for.
Serving and Storage for Low Carb Lemon Texas Sheet Cake
- Cut into 24 squares in the pan once the glaze sets, about an hour
- Keeps 4 days covered at room temperature
- Refrigerates up to a week; glaze firms cold and softens back at room temperature
- Freezes well as cut squares, wrapped tight, for 3 months
Make-Ahead Texas Sheet Cake
This cake is better on day two. The lemon deepens overnight and the crumb settles. Bake it the day before a gathering, glaze it hot as directed, and leave it covered on the counter — no reheating needed. That resting period is part of why this low carb Texas sheet cake works so well for a crowd; it can be made a full day ahead without losing anything, which frees up oven space right before serving.
Every sweetened recipe on this site draws from the same short list of substitutes — allulose, erythritol, monk fruit, and Carbquik all show up in this one. The reasoning behind that list — what makes the cut, what gets left on the shelf, and why — is laid out on the Low Carb Ingredient Substitutes guide.
Texas Sheet Cake, Low Carb Lemon
Ingredients
Cake:
- 1 cup butter salted
- ½ cup water
- ¼ cup lemon juice fresh
- 2 cup Carbquik
- 1 cup almond flour superfine
- 1¼ cup allulose granular
- ¾ cup monk fruit erythritol blend granular
- 1 tsp baking soda
- ½ tsp salt
- ½ cup sour cream full-fat
- 3 egg
- 2 Tbsp lemon zest
- 1 tsp lemon extract
- ½ tsp vanilla extract
Lemon Glaze:
- ½ cup butter salted
- 3 Tbsp lemon juice fresh
- 2 Tbsp heavy cream
- 1½ cup allulose powdered
- ¼ cup monk fruit erythritol blend powdered
- 1 tsp lemon zest
Instructions
Cake:
- Melt butter in a saucepan over medium heat
- Add water and lemon juice
- Bring to a light boil
- Remove from heat and rest 5 min
- Whisk Carbquik, almond flour, granular allulose, granular monk fruit blend, baking soda and salt in a large bowl.
- Pour hot butter mixture over dry mixture
- Whisk smooth
- Whisk in sour cream, eggs, zest, lemon extract and vanilla
- Pour into a greased 12″x17″ sheet pan
- Spread level
- Bake in a 325°F preheated oven 22 min until center springs back and edges pull from pan.
Lemon Glaze:
- Melt butter in a sm saucepan
- Stir in lemon juice and cream
- Remove from heat
- Whisk in powdered allulose, powdered monk fruit blend, and zest until smooth and pourable.
- Pour over hot cake
- Spread to edges with an offset spatula
- Cool 1 hr until glaze sets
Notes
Bake at 325°F, not 350°F — allulose browns noticeably faster than sugar.
Glaze must hit the cake hot so it soaks the top surface instead of sitting on it.
Powdered sweeteners only in the glaze; granular stays gritty no matter how long it cooks.
Fresh lemon juice only; bottled juice bakes out flat.
Keeps 4 days covered at room temperature, 1 week refrigerated.