Place deep dish baking pan plates on the grill. Use switch at bottom right rear of grill to make flat surface. Close cover; set cooking temperature at 400°F and cooking time for 12 minutes. Allow grill to preheat for 5 minutes.
In a large bowl, stir together flour, brown sugar, baking powder, pumpkin spice blend, baking soda and salt. Cut in butter until it resembles coarse crumbs. In a separate bowl, stir pumpkin with buttermilk; stir into flour mixture just until moistened.
Turn dough out onto lightly floured surface. Sprinkle butterscotch chips over dough and knead just until evenly incorporated (do not overmix). Pat into 1/2-inch thick round; using ½-inch round cutter, cut out 20 2-inch biscuits. Arrange on baking pan; bake for 12 minutes or until golden brown. Let cool completely. (Biscuits can be made up to 12 hours ahead.)
Toss together blackberries, sugar and lemon juice; let stand for 10 minutes. Meanwhile, beat cream with maple syrup using an electric mixer on high until it holds soft peaks. Halve biscuits; place bottom half of each biscuit on a dessert plate. Top with blackberries and whipped cream; cap with biscuit top. Serve immediately.