01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - Toss pitted and halved cherries with 1 tablespoon sugar and 1 teaspoon vanilla extract. Spread on prepared baking sheet and roast for 12-15 minutes until juicy and slightly caramelized. Let cool completely.
03 - Reduce oven temperature to 350°F. Grease an 8-inch square baking pan and line with parchment paper, leaving overhang for easy removal.
04 - Set a heatproof bowl over a saucepan of simmering water. Melt butter and chopped chocolate together, stirring constantly until smooth. Remove from heat and cool slightly.
05 - Whisk granulated and brown sugars into melted chocolate mixture. Add eggs one at a time, whisking well after each addition. Stir in vanilla and salt.
06 - Sift flour and cocoa powder into the batter. Gently fold until just combined, taking care not to overmix.
07 - Gently fold most of the roasted cherries into the batter, reserving a few pieces for topping.
08 - Pour batter into prepared pan and smooth the top with a spatula. Scatter reserved roasted cherries evenly 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 for fudgy texture.
10 - Cool completely in the pan before lifting out using parchment overhang. Cut into squares and serve.