Process all ingredients except butter in a blender until smooth.
Preheat oven broiler.
Melt butter in a 7- or 8-inch nonstick skillet or omelet pan. Pour in tofu batter and spread evenly with a spatula. Cook, without stirring, over medium heat for a few minutes until the edges are set but not browned. The batter will bubble up as the excess liquid evaporates.
Remove from burner and place under preheated broiler for 2 to 3 minutes until the top is set and has just a hint of brown.
Remove from broiler and add your favorite filling. If desired, to one half of the omelet. Using a spatula, carefully fold another half of omelet over the filling. The omelet is delicate, and if it breaks a little, just smooth it with your spatula. Spread the top with butter, if desired.
Place under broiler again for 1 to 2 minutes until golden brown. Serve at once.