Use a dry red wine with full-bodied notes—such as plum or cherry. You will need ½ cup to add depth of richness to the chocolate.
Melt ½ cup of unsalted butter and 170 grams dark chocolate in a saucepan over low heat. Heat until smooth and glossy. Let cool slightly.
Whisk together 2 eggs, ¾ cup sugar, 1 tsp vanilla, and your red wine. Blend till the mixture becomes silky and color deep.
Fold in ½ cup flour, ¼ cup cocoa powder, and a pinch of salt. Stir until just combined, then stir in the melted chocolate mixture.
Pour into a lined 8x8-inch pan. Bake at 175°C for 25–30 minutes. Allow the brownies to cool before cutting. Dust with cocoa or sea salt as a final touch.