In a large bowl, combine mushrooms, zucchini pulp, ⅔ of the garlic, diced tomato (reserving a bit for garnish), nutritional yeast, dried basil, oregano, half the fresh basil, red pepper flakes to taste, and salt and pepper to taste. Once mixed, add 1 Tbsp. olive oil. Add breadcrumbs, a little at a time, until a slightly firm stuffing mixture has formed. Mixture should be a consistency that can be easily pressed together and into the zucchini.