Preheat oven to 180°C (top and bottom heat). Open the seal and empty the contents into a large bowl.
Melt the 60g butter either in a bowl over a bain-marie or in the microwave and add it to the baking mix along with 100ml of water (see the water line in the can). Then mix for 1 minute using a food processor, hand mixer, or the Thermomix (speed 3-4 with the spatula) until a smooth batter forms.
Stir the pitted cherries into the batter.
Pour the finished winter brownie batter into an 18x18 cm baking pan or a similarly sized baking pan. Then spread the batter evenly in the pan.
Bake the dough for 25 minutes at 180°C top and bottom heat.
Allow the baked winter brownies to cool completely on a wire rack.
After baking, garnish with melted chocolate and powdered sugar.