Bring a large pot of salted water to a boil. Boil the shells for 8-9 minutes or until almost al dente, but still have a little bite. Drain and rinse with cold water. Set aside.
While the shells are boiling, prepare your sauce. In a large nonstick skillet, add the sausage. Cook over medium heat until brown and almost cooked through. Add the onion, and cook for an additional 5 minutes. Add the garlic and cook for 1 more minute. Stir in the tomato paste and continue cooking for about 2 minutes or until it takes on a deep red color. Stir in the chicken broth, 1/2 cup at a time until it reaches your desired consistency. This will range from 1-2 cups depending on your preference. Bring to a simmer and add the Italian seasoning, chili powder, granulated sugar, and salt and black pepper to taste. Reduce the heat to low and cook for 5-6 minutes more. Adjust seasoning to taste and keep over low heat until you are ready to serve.
In a small bowl, stir together the ricotta cheese, 1/4 cup parmesan cheese, oregano, egg white, and a dash of salt and black pepper. Spoon the cheese mixture into the shells and place the shells directly in the pan with the sauce. Sprinkle the remaining 2 tablespoons of parmesan cheese on top and cover. Cook until the cheese has melted and then remove from heat.
Serve immediately garnished with fresh parsley and additional parmesan if desired. Enjoy!
Tomato past is EXTREMELY acidic. It's literally concentrated tomatoes. To cut through that acidity, add sugar or something similar like honey. A teaspoon may not be enough, so taste it as you go along and add more as needed.