Preheat an oven to 350°F. Prepare a square baking pan with aluminum foil and spray with oil; set aside.
Slice the zucchini thin (with a knife or mandoline). Spray with a little oil then roast on a sheet pan in the oven for 15-20 minutes until browned but not crispy. When done set aside to cool.
Sauté the meats with chopped onion and 4 minced garlic cloves in a large skillet until browned. Add the crushed tomatoes and cook for additional 40 minutes on low and let cool.
Puree the mascarpone, basil leaves, 2 cloves of garlic, a dash of salt and egg in a food processor until smooth; set aside.
Layer the zucchini, meat sauce then mascarpone two times. Top with cheese and bake for one hour covered with aluminum foil. Remove the foil and bake an additional 15 minutes. Serve immediately or allow it to fully cool and then place in the refrigerator overnight and pull out and slice into 6 servings.