Preheat your oven to 400°F (200°C). Cut fresh cherries in half and spread them evenly on a lined baking sheet. Lightly sprinkle with granulated sugar, then roast for about 10 minutes or until they soften.

Reduce oven temperature to 325°F (160°C). Spray an 8x8 inch baking pan with non-stick spray and line it with parchment paper.

In a medium bowl, sift together the all-purpose flour, Dutch process cocoa powder, cornstarch, and salt. Set aside.

In a separate bowl, whisk together the eggs, egg yolk, and granulated sugar on high speed for about 5 minutes until pale-yellow and fluffy.

Melt the unsalted butter and allow it to cool slightly, then add to the egg mixture with canola oil and vanilla extract. Mix on low speed until well combined.

Gently fold the sifted dry ingredients into the wet mixture. Add half of the roasted cherries and chocolate chips, folding gently.

Pour the batter into the prepared pan, smoothing it evenly. Bake for about 40-50 minutes, checking doneness with a toothpick.

Let the brownies cool in the pan for about 30 minutes, then transfer to the freezer for another 15 minutes. Top with remaining roasted cherries, slice, and serve warm.