In large skillet, brown sausage over medium-high heat until thoroughly cooked and no longer pink, stirring frequently. Add onions and cook until tender. Stir in tomato paste and cook until thoroughly heated.

Meanwhile, heat oven to 375°. In small bowl, combine all cheese filling ingredients; blend well. Unroll both cans of dough into 2 large rectangles. Place dough with long sides together on ungreased cookie sheet. Firmly press edges and perforations to seal. Press to form 15x13" rectangle.

Spoon half of meat filling in 6"-wide strip lengthwise down center of dough to within 1" of short sides. Spoon cheese filling over meat filing; spoon remaining meat filling evenly over cheese filling; arrange mozzarella cheese slices over meat filling.

Fold short sides of dough 1" over filling. Fold long sides of dough tightly over filling, overlapping edges in center 1/4". Firmly pinch center seam and ends to seal. Brush with milk. Sprinkle with sesame seeds.

Bake at 375° for 23-27 minutes or until deep-golden brown.