01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - Toss pitted and halved cherries with 1 tbsp sugar and 1 tsp vanilla extract. Spread on the prepared baking sheet and roast for 12-15 minutes, until juicy and slightly caramelized. Let cool.
03 - Reduce oven temperature to 350°F. Grease and line an 8-inch square baking pan with parchment paper, leaving an overhang for easy removal.
04 - In a heatproof bowl set over a saucepan of simmering water, melt butter and chopped chocolate, stirring until smooth. Remove from heat and cool slightly.
05 - Whisk in granulated and brown sugars, followed by eggs, one at a time. Stir in vanilla and salt.
06 - Sift in flour and cocoa powder, and gently fold until just combined.
07 - Fold in most of the roasted cherries, reserving a few for topping.
08 - Pour batter into the prepared pan and smooth the top. Scatter reserved cherries over the surface.
09 - Bake for 25-28 minutes, or until a toothpick inserted in the center comes out with moist crumbs. Do not overbake.
10 - Cool completely in the pan before cutting into squares.