Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper and spread the halved fresh cherries in a single layer. Sprinkle with sugar and roast for 10 minutes.

Lower the oven temperature to 325°F (163°C). Prepare an 8X8 inch baking pan with non-stick spray and parchment paper.

Sift together the all-purpose flour, Dutch process cocoa powder, cornstarch, and salt in a mixing bowl.

In a separate bowl, beat the eggs, egg yolk, and sugar on high for about 5 minutes until pale and frothy. Gradually add melted butter, oil, and vanilla.

Gently fold the dry ingredients into the egg mixture. Fold in half of the roasted cherries and all the chocolate chips.

Spread the brownie batter into the prepared pan and bake for 40-50 minutes. The edges should be set, and a toothpick should come out with a few moist crumbs.

Cool in the pan for 10 minutes, then transfer to the refrigerator for 15 minutes. Top with remaining roasted cherries before serving.