Preheat oven to 325°. In a large bowl, cream butter and brown sugar until light and fluffy, 5-7 minutes. Add eggs, 1 at a time, beating well after each addition. Beat in pumpkin, molasses and orange zest (mixture will appear curdled)., In a small bowl, combine flour, baking soda, ginger, cinnamon, salt and chili pepper. Add to creamed mixture alternately with buttermilk, beating well after each addition. Stir in pumpkin seeds., Pour batter into a greased 9-in. square baking pan. Bake until a toothpick inserted in center comes out clean, 28-32 minutes. Cool completely on a wire rack. Serve with toppings as desired.