- With the rack in the middle position, preheat the oven to 350°F (180°C). Butter 36 non-stick mini-muffins cups or line with paper liners.
- In a bowl placed over a pot of simmering water, melt the chocolate. Allow to cool. Set aside.
- In another bowl, cream the butter, brown sugar and salt with an electric mixer. Add the egg and egg yolk and beat until frothy and smooth. At low speed, add the flour alternating with the milk. With a spatula, gradually fold in the chocolate.
- Divide the batter among the muffin tins. Bake for about 14 minutes or until the brownies are just cooked. Repeat with the remaining batter. Let cool and unmould.