Preheat oven to 350°F.
Cook ziti pasta with salt in a large pot until al dente. Drain, then add 1 tbsp olive oil to the pasta, mix.
Sauce. Heat 1 tbsp olive oil in a large skillet over medium-high heat, add ground beef, cook until brown (don't forget to break up the chunks). Add chopped onions and saute about 4-5 mins. Then add minced garlic, rosemary, Italian seasoning, and red pepper flakes, mix and saute one more minute. Add marinara sauce, mix well, bring to a simmer and remove from the heat.
Add a spoonful of sauce to the cooked ziti and mix.
Spread about 1/4 cup sauce on the bottom of the 9x13 baking pan, add half of the ricotta cheese. Then add cooked ziti, spread evenly. Put the rest of the sauce on top of the pasta, add the remaining ricotta cheese, then sprinkle with mozzarella and parmesan cheese.
Bake in the preheated oven for 15-20 mins until cheese melts and lightly browned.