Great Grandma's Lasagna

What You Need

• 1 lb. lean ground beef
• 1/3 cups onion, chopped
• 1/4 cup green peppers, chopped
• 1/4 cup mushrooms, sliced
• 2 cups canned seasoned tomatoes
• 5 Tbsp. tomato paste
• 1 1/2 tsp. salt
• 1 1/2 tsp. black pepper
• 1 tsp. oregano
• Shredded mozzarella cheese
• Ricotta cheese
• 9 lasagna noodles