In a medium size-mixing bowl, whisk together the eggs, heavy cream, parmesan, and salt and pepper. Set aside.
Break up and brown the sausage in an ovenproof skillet over medium heat, (I like cast iron for this).
When the sausage is broken up, but not completely browned, add the dried oregano and chopped onion. Sauté until the sausage is cooked through and the onion softens, and turns translucent.
Add the mushrooms and sauté until they soften and lose most of their liquid.
Add minced garlic and sauté until it just turns fragrant, about a minute.
Pour the egg mixture into the pan. Spread mixture so that it is evenly dispersed.
In order, sprinkle the quartered grape tomatoes, fresh basil, and shredded mozzarella over the top of the egg-sausage mixture.
Transfer skillet to a 400-degree oven and bake for about 10 minutes, or until puffed, golden, and cooked through.
Rest for 5 minutes, then slice and serve.