Preheat your oven to 400°F.
Arrange cherry tomatoes, mushrooms, and garlic in a greased 9×13 baking dish.
Drizzle with olive oil, sprinkle with salt, pepper, and red pepper flakes, then toss to coat.
Create space in the center for the Boursin cheese round, surrounded by the tomatoes and mushrooms.
Bake for 30 minutes until tomatoes burst, mushrooms roast, and cheese melts.
Meanwhile, cook pasta in salted boiling water until al dente.
Drain, reserving 1 cup of cooking liquid.
Once baked, add spinach to the dish, stirring until wilted and combining with the melted cheese to form a sauce.
Add drained pasta to the pan, tossing and adjusting consistency with reserved pasta water as needed.