Prep your pan and oven: Preheat the oven to 350°F (175°C). Line an 8x8-inch pan with parchment, leaving overhang on two sides for easy lifting. Lightly grease the parchment.

Melt butter and chocolate: In a heatproof bowl, melt 1/2 cup butter and 3/4 cup sugar-free chocolate together using short microwave bursts or a double boiler. Stir until smooth and glossy. Cool 3–4 minutes.

Whisk in sweetener: Add 2/3 cup keto sweetener to the warm chocolate mixture and whisk until it looks thick and uniform. This helps dissolve the sweetener for a better texture.

Add eggs and vanilla: Whisk in 2 large eggs, one at a time, until the batter becomes shiny and slightly thick. Stir in 1 teaspoon vanilla. If using, add 1/2 teaspoon espresso powder.

Dry ingredients: Sift together 1/2 cup cocoa powder, 3/4 cup super-fine almond flour, 1/4 teaspoon baking powder (optional), and 1/2 teaspoon sea salt. Fold into the wet mixture just until combined. The batter will be thick.

Optional add-ins: Fold in 1/3 cup chopped nuts or a small handful of sugar-free chocolate chips for extra richness.

Spread and smooth: Scrape batter into the pan and smooth the top with an offset spatula. Tap the pan lightly on the counter to level.

Bake: Bake 18–22 minutes until the edges are set and the center is just barely firm with a slight jiggle. A toothpick should come out with moist crumbs, not wet batter.

Cool completely: Let the brownies cool in the pan on a rack for at least 45–60 minutes. For the fudgiest slices, chill 30 minutes before cutting.

Slice and serve: Lift out using parchment and cut into 12 squares with a sharp knife, wiping the blade between cuts for clean edges.