Prep the pan and oven: Preheat the oven to 350°F (175°C). Line an 8-inch round cake pan or square pan with parchment and lightly grease the sides.
Mix dry ingredients: In a large bowl, whisk 2 cups almond flour, 2 tablespoons coconut flour, 2 teaspoons baking powder, and 1/4 teaspoon fine sea salt until well combined.
Whisk wet ingredients: In a separate bowl, whisk 3 large eggs, 1/2 cup keto granulated sweetener, 1/3 cup melted butter, 1/2 cup sour cream, 1 teaspoon vanilla, and 1/4 teaspoon almond extract.
Add 1 teaspoon lemon zest if using.
Combine: Pour the wet mixture into the dry and stir until just smooth. The batter will be thick but spreadable. If it seems too thick, add 1–2 tablespoons of milk or water to loosen slightly.
Prep strawberries: Hull and slice 1 cup of strawberries.
Pat them dry with a paper towel so they don’t bleed too much into the batter.
Fold and spread: Gently fold half the strawberries into the batter. Spread the batter evenly in the pan. Scatter the remaining strawberries on top.
Add crunch: Sprinkle 2–3 tablespoons of sliced almonds across the top for texture and a golden finish.
Bake: Bake for 28–35 minutes, until the edges are golden and a toothpick comes out mostly clean with a few moist crumbs.
Avoid overbaking.
Cool: Let the cake cool in the pan for 15 minutes, then lift it out using the parchment to a rack. Cool completely for neat slices.
Finish: Dust with powdered keto sweetener if you like. Slice and serve warm or at room temperature.