Make hot-roll mix according to directions on the box.
Cook cabbage and onion in butter until wilted.
Add tuna, flaked, and dillweed.
Season to taste with salt and pepper.
After dough has risen, divide into halves and roll each half into a rectangle about 9 x 11 inches.
Put one rectangle in a shallow baking pan and spread with tuna-cabbage mixture.
Moisten edges, top with second rectangle, and seal.
Brush the top with egg beaten with water.
Bake in preheated hot oven (400° F.) for 15 to 20 minutes, or until nicely browned.
Cut into squares.
Makes 12 servings.