Prep the pan and oven. Heat the oven to 350°F (175°C). Grease a 9-inch springform pan or regular cake pan. Line the bottom with parchment and lightly grease the paper. This helps the delicate cake release cleanly.

Melt chocolate and butter. Place the chopped chocolate and butter in a heatproof bowl. Set over a pot of gently simmering water (do not let the bowl touch the water) and stir until smooth. Alternatively, microwave in 20–30 second bursts, stirring between each, until melted. Remove from heat and let cool 5 minutes.

Combine dry ingredients. In a small bowl, whisk almond flour, salt, and espresso powder (if using) to break up clumps. Set aside.

Whisk in sugars and extracts. To the slightly cooled chocolate mixture, whisk in the granulated and brown sugars until glossy. Add vanilla and almond extracts. The mixture may look thick—that’s fine.

Add the eggs. Whisk in the eggs one at a time, mixing until fully incorporated before adding the next. The batter will become shiny and smooth. Avoid overmixing once the eggs are in.

Fold in almond flour. Add the almond flour mixture and gently fold with a spatula until no dry streaks remain. The batter will be pourable but thick.

Fill the pan. Scrape the batter into the prepared pan and smooth the top. Tap the pan once on the counter to release air bubbles.

Bake. Bake for 22–28 minutes, until the edges are set and the center is just slightly soft and jiggles a bit. A toothpick inserted 2 inches from the edge should come out with a few moist crumbs; the very center may look a touch underdone.

Cool. Set the pan on a rack and cool for 10–15 minutes. Run a thin knife around the edge, then release the springform ring (or gently invert if using a regular pan and peel off the parchment). Cool to room temperature. The cake will settle slightly as it cools.

Finish and serve. Dust with cocoa or powdered sugar if you like. Slice with a warm knife for clean edges. Serve plain or with berries and whipped cream.