Scrub potatoes, then dry and pierce. Bake at 400° for about an hour on a rack without foil. Melt butter and saute onion. Halve the potatoes lengthwise. Scoop out the pulp while leaving shell intact. Mash potatoes. Add M-K Cayenne Red Pepper, M-K Granulated Black Pepper, salt, butter, onion and cheese. Beat in enough milk to create a fluffy consistency. Fill 6 to 8 of the potato shells. Pile high and score tops with a fork. Bake only until tops are lightly brown. Serves 6 to 8.