Crush cones to coarse crumbs in food processor. Mix with butter, brown sugar. Press mixture evenly into bottom of a 9-inch square baking pan with Teflon™ nonstick coating, Prepare brownie mix accordingly; pour into pan, spreading evenly over the crust. Bake at 325° for 45 minutes until tester holds a few fudgy crumbs (don’t over-bake; keeps crust from burning). Cool completely on a wire rack; loosen edges with a flexible spatula and turn out onto a flat surface; cut into squares and serve with ice cream.