Melt butter and dark chocolate using a microwave in 30-second intervals until fully melted and mixed.

In a separate bowl, lightly beat the eggs.

Add sugar and salt to the beaten eggs and mix well.

Warm the egg mixture to match the temperature of the melted chocolate and butter.

Combine the egg mixture with the melted chocolate and butter, mixing thoroughly.

Sift the dry ingredients (flour and cocoa powder) and fold them into the chocolate mixture.

Add vanilla extract and mix until just combined.

Pour the batter into a round baking tin and tap the tin 2-3 times to remove air bubbles.

Bake in a preheated oven at 180°C for 40 minutes.

Cool the brownie in the tin at room temperature before removing and peeling off the parchment paper.