Slice the tomatoes in 1/2 inch thick slices. Mix flour, sugar, salt, and pepper on a piece of wax paper. Coat the tomato slices with the flour mixture. Melt 1 Tablespoon of butter in a large skillet over medium heat. Add tomatoes in a single layer. Cook 3 - 4 minutes per side, until light brown and just barely tender. Remove to a serving platter. Repeat with the remaining tomato slices.