Preheat oven to 350°F.
In a large skillet over medium heat, brown 1 lb ground beef and drain excess grease.
Stir in 28 oz crushed tomatoes, 1 tablespoon Italian seasoning, and 1 teaspoon garlic salt. Mix well and let simmer briefly.
Meanwhile, cook 16 oz penne pasta in salted water until al dente (slightly undercooked). Drain well.
Pour half of the cooked pasta (about 8 oz) into a 9×13 baking dish.
Spoon half of the meat sauce mixture over the pasta.
Sprinkle 1 ½ cups mozzarella cheese over the top.
Add half of the pepperoni (3 oz) evenly over the cheese.
Repeat the layers: add remaining pasta, remaining meat sauce, remaining 1 ½ cups mozzarella cheese, and remaining 3 oz pepperoni.
Sprinkle ¼ cup parmesan cheese evenly over the top.
Cover with foil and bake at 350°F for 30 minutes.
Remove foil and bake an additional 15 minutes until hot, bubbly, and lightly browned.
Let cool for 5 minutes before serving.