Preheat your oven to 400°F (200°C). Cut the fresh cherries in half, remove the pits, and arrange them cut-side up on a parchment-lined baking sheet. Sprinkle a light layer of sugar over the cherries. Roast for about 10 minutes until softened. Allow to cool.
In a large mixing bowl, sift together all-purpose flour, Dutch process cocoa powder, cornstarch, and salt. Set aside.
In a mixer, beat together granulated sugar, eggs, and egg yolk on high speed for 5 minutes. Lower the speed and gently add melted butter, canola oil, and vanilla extract. Mix until combined.
Gently fold the sifted dry ingredients into the wet mixture. Once combined, fold in half of the cooled roasted cherries and semi-sweet chocolate chips.
Prepare an 8x8 inch baking pan with parchment paper. Pour brownie batter into the pan and spread evenly. Bake at 325°F (160°C) for 40-50 minutes. The edges should be set, the center slightly underbaked. Check with a toothpick.
Allow the brownies to cool in the pan for 20-30 minutes, then transfer to freezer for 15 minutes. Top with remaining roasted cherries, slice, and enjoy!