Preheat oven to 425°F.
Grease a 13" X 9" casserole dish.
In a large bowl, stir together marinara sauce, beef broth, tomato paste, minced garlic, Italian seasoning, salt and pepper until well combined.
Spread ½ the uncooked pasta in the bottom of the prepared casserole dish in an even layer.
Using your fingers, break up the sausage into small ½ inch pieces. Scatter ½ the sausage as evenly as possible over the top of the pasta.
Using a teaspoon, dollop ½ the ricotta cheese as evenly as you can, over the pasta and sausage in the cassserole dish.
Top using ½ the sliced mushrooms.
Pour half the marinara sauce as evenly as you can over the pasta, sausage, ricotta cheese, and mushrooms in the casserole dish.
Sprinkle with ½ the grated Parmesan cheese.
Repeat to make a second layer with the remaining ingredients.
Cover casserole dish with foil and bake for 50 minutes.
Uncover casserole and top evenly with shredded mozzarella cheese.
Return uncovered casserole dish to the oven and bake for an additonal 10-15 minutes, until cheese is melted, bubbly and beginning to brown slightly along the edges.
Allow casserole to rest for 10 minutes before serving.