Preheat your oven to 200°C (390°F) and prepare a 24 cm (9.5-inch) springform pan by greasing it with butter or lining with parchment.

In a medium mixing bowl, whisk together 3 large eggs, 350 g of granulated sugar, 1 tsp of pure vanilla extract, and 0.5 tsp of salt until combined and creamy.

Sift in 120 g of all-purpose flour and 45 g of cocoa powder into the egg mixture. Mix gently until just combined.

Melt 150 g of unsalted butter and stir it into the batter until combined.

Pour the batter into the prepared springform pan and bake for about 17 minutes, until the outer edge is set but the center is slightly wobbly.

Remove from the oven and allow to cool in the pan for about 5 minutes before transferring to a serving plate. Dust with powdered sugar if desired.