Heat oven to 400°. Place berries in a large bowl. Add sugar, flour, lemon juice, and cinnamon. Toss to combine. Set aside.

Spoon the berry mixture into the pie crust, and lay the second pie crust over the fruit. Trim away excess pastry, trim an opening of about 3 inches in the center. Chill cobbler in the refrigerator until dough is firm, 15 to 20 minutes.

Combine egg yolk and cream in a small bowl. Brush pastry with the egg wash. Place cobbler in oven. Bake until crust is golden, about 30 minutes. Reduce heat to 350°. Continue baking until juices start to bubble up over the crust, about 35 minutes more. Remove from oven, cool slightly, and serve.