Prep the pan and oven: Preheat your oven to 325°F (163°C). Line a 9x5-inch loaf pan with parchment paper, leaving a slight overhang for easy removal. Lightly grease the parchment and sides.

Whisk dry ingredients: In a bowl, whisk 2 cups super-fine almond flour, 2 tablespoons coconut flour, 1 1/2 teaspoons baking powder, and 1/2 teaspoon salt. Set aside.

Cream butter, cream cheese, and sweetener: In a large mixing bowl, beat 1/2 cup softened butter and 4 ounces softened cream cheese until smooth, about 2 minutes. Add 3/4 to 1 cup granular keto sweetener (to taste) and beat until fluffy, 2–3 minutes.

Add eggs and flavorings: Beat in 4 large eggs, one at a time, mixing well after each. Scrape the bowl as needed. Stir in 1 teaspoon vanilla extract, optional 1/4 teaspoon almond extract, and 1 teaspoon lemon zest.

Mix in sour cream: Add 1/3 cup sour cream and mix until incorporated. The batter should look creamy and slightly thick.

Combine wet and dry: Add the dry mixture to the wet ingredients and mix on low just until combined. Do not overmix. The batter will be thick but spreadable.

Fill the pan: Transfer batter to the prepared loaf pan and smooth the top with a spatula. Tap the pan gently on the counter to release air pockets.

Bake: Bake for 55–70 minutes, or until the top is golden and a toothpick inserted in the center comes out mostly clean with a few moist crumbs. If the top browns too quickly, tent loosely with foil during the last 15 minutes.

Cool properly: Let the cake cool in the pan for 15 minutes, then lift it out using the parchment and transfer to a wire rack. Cool completely before slicing for the cleanest cuts.

Serve: Slice and enjoy as is, or serve with lightly sweetened whipped cream and berries. For a café-style treat, toast a slice and add a pat of butter.