Preheat the oven broiler on low.
Heat the oil in a large broiler-safe non-stick or cast-iron skillet over medium heat. Add garlic and cook, stirring frequently, until golden brown.
Pour the eggs into the pan along with the parmesan. Cook for 1-2 minutes, then remove the pan from the heat. Arrange the zucchini, tomatoes, and mozzarella on top and season with salt and pepper. Place the skillet under the broiler until the eggs are firm in the middle and slightly browned on top, about 6-10 minutes. Let sit for 3 minutes. Top with basil.
For the chicken sausage: If raw, cook in a 400°F oven to an internal temperature of 160°F using a thermometer. If already cooked: Preheat a non-stick pan over medium heat and brown the chicken sausage slices on each side. Toast the bread. To release the frittata from the pan, run a spatula around the edge, then underneath, until you can slide or lift it out onto a cutting board or serving plate.
Cut into wedges and serve with toast and raspberries.