In a large bowl, combine the peaches, blackberries and lemon juice and toss to coat well. Add the sugar, cornstarch, and cinnamon and toss to combine well, taking care not to break up the berries. Transfer to a 4-quart grill-proof or ovenproof baking dish. Allow to sit while you make the topping.

Preheat the grill to low/medium-low heat, around 350 to 400 degrees F or an oven to 375 degrees F.

Combine the butter and sugars in a medium mixing bowl. Using a handheld mixer, cream together until light and fluffy. Combine the pecans and remaining dry ingredients in a second bowl and stir to blend well. Add the dry ingredients to the butter mixture and mix on low until everything comes together and mixture begins to clump together; take care not to overmix. The topping should be a crumbly mass that sticks together when you press it between your fingers. Sprinkle it evenly over the surface of the cobbler.

Transfer the cobbler to the grill over indirect heat, cover the grill, and adjust the settings so that the temperature hovers as close as possible to 350 degrees F (or to a preheated oven). Cook until the fruit is very bubbly with thick juices around the edges of the pan and the topping is golden brown and cooked through, usually 55 to 60 minutes.

Serve warm with scoops of vanilla ice cream or whipped cream, if desired.

Serves 8 to 10

*Cook’s Note:  The quickest and easiest way to peel peaches is to submerge them in boiling water for 30 seconds. Transfer immediately to an ice bath until cool enough to handle, then peel them by slipping the skins off.