Cobbler topping is like scone meeting cake—the heat of the oven creates a lovely crunchy top to the cobbler and the steam from the baking fruits creates a moist, cake-like interior.
Toss the peaches, raspberries, and blueberries with 3 Tbsp (45 mL) of the sugar and ¼ tsp (1 mL) of the cinnamon, and spread the mixture on the bottom of an 8-cup (2 L) baking dish (preferably ceramic—see the section on baking pan choices for more on pan choice).