Coarsely chop the pecans. Finely chop the chocolate. Melt 300 g chocolate with 100 g butter in a pot. Mix flour, 150 g pecan nuts, cinnamon and salt. Beat the eggs and 160 g sugar with the whisk of the hand mixer. Gradually stir the melted chocolate and 4 tbsp. liqueur into the egg mixture and finally add the flour mixture. Spread the dough into a square springform pan (24 x 24 cm) lined with baking paper and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 20 minutes. Take out and let cool down.
Wash, clean and stone fresh cherries. Caramelise 75 g sugar in a pot. Deglaze with port wine and kirsch and let it boil down to half. Add the cinnamon stick. Mix 10 g starch with 2 tbsp. cold water, stir into the stock and simmer for about 1 minute, stirring continuously. Add cherries and bring to the boil briefly. Pour compote into a container and let it cool down, then put it in a cool place.
Mix 8 g starch with 1 tablespoon cold water. Bring milk and 75 g sugar to the boil in a saucepan and stir in the mixed starch. Simmer for about 1 minute while stirring constantly. Let the milk sauce cool down and then fill it into an Espuma bottle (cream dispenser). Put the bottle in a cool place.
Heat the cream in a small pot, stir in 200 g chocolate and 4 tbsp. liqueur until a shiny mass is formed. Spread the chocolate icing on the brownie and chill for about 30 minutes. Heat 1 tsp. butter in a small pan. Add 50 g pecan nuts and 1 tbsp. sugar and allow to caramelise. Take out and let it cool down on a piece of baking paper.
Spread caramelized pecans on the brownie and cut into about 16 pieces. Serve the brownie with milk foam from the Espuma bottle and cherry compote.