In 10-inch skillet, cook sausage and beef over medium-high heat, stirring frequently, until thoroughly cooked and no longer pink. Drain. Stir in remaining meat filling ingredients; cook about 5 minutes, stirring occasionally, until hot.
Meanwhile, heat oven to 375 degrees F. In small bowl, mix cheese filling ingredients.
If using crescent rolls: Unroll both cans of dough into 4 long rectangles. On ungreased cookie sheet, place dough rectangles side by side; firmly press edges and perforations to seal. Press to form 15x13-inch rectangle. If using dough sheets: Unroll both cans of dough. On ungreased cookie sheet, place dough rectangles side by side; firmly press edges to seal. Press to form 15x13-inch rectangle.
Spoon half of meat filling in 6-inch-wide strip lengthwise down center of dough to within 1 inch of short sides. Spoon cheese filling over meat filling; spoon remaining meat filling evenly over cheese filling. Arrange mozzarella cheese slices over filling.
Fold short sides of dough 1 inch over filling. Fold long sides of dough tightly over filling, overlapping edges in center 1/4 inch; firmly pinch center seam and ends to seal. Brush with milk; sprinkle with sesame seed.