Unfold phyllo dough and cover with plastic wrap. Lay a sheet of phyllo dough flat on work surface. Brush with a little of the melted butter. Top with another sheet of phyllo and brush with more of the butter. Repeat with the remaining sheets of phyllo dough and butter to make one phyllo stack.
Carefully cut a 10- to 11-inch circle from the phyllo stack. Cover and reserve the trimmings to garnish the top.
Spread mustard on top of Gouda cheese. Place cheese, spread side down, in center of the circle of phyllo dough.
Gently bring the edges of the pastry up and over the cheese, pleating and pinching to seal. Brush bundle with some of the remaining butter.
Cut decorative designs from the phyllo trimmings and place on the seam side of the bundle, brushing with butter. Wrap the bundle in clear plastic wrap or foil and freeze for 1 hour.
To serve, unwrap the frozen bundle and place, seam side up, on a foil-lined baking sheet. Bake in a 400 degree F. oven about 12 minutes or until the pastry is golden brown and cheese is just softened. Let stand about 5 minutes before serving. Serve with fruit, bread and/or crackers. Makes 6 servings.