Put tomatoes on an foil lined baking sheet. Drizzle with olive oil and season with salt and pepper. Roast at 400 for 20 minutes.
In a large saucepan, heat olive oil over medium heat. Add garlic and shallots and cook until fragrant, 2-3 minutes. Add tomato sauce and chopped tomatoes and bring to a boil. Stir in tomato paste and vodka, reduce heat and simmer until sauce has reduced by at least 1/3.
Meanwhile, bring a large pot of salted water to a boil and cook gnocchi according to the box’s instructions. Fresh gnocchi will only take 1-2 minutes. Melt butter in a saute pan over medium, low heat. Add mushrooms and cook until tender, 7-8 minutes. Add vermouth, 1 tablespoon cream and sage. Mix well and continue cooking until almost all the liquid has evaporated.
Put drained gnocchi into greased baking dish. Top with mushrooms, then roasted tomatoes
Stir remaining 1 cup of cream and the Parmesan cheese into the tomato vodka sauce, cooking on low heat until cheese is melted.
Pour sauce over gnocchi until covered. Reserve extra sauce for serving. Top casserole with more Parmesan. At this point dish can be refrigerated until baking. Bake at 325 30-40 minutes until heated through and bubbly. Serves 4-6