Preheat the oven to 400°F (200°C). Line a rimmed baking sheet with parchment paper.
Place the cherry tomatoes and smashed garlic cloves on the baking sheet. Drizzle with olive oil and sprinkle with kosher salt, black pepper, and red pepper flakes. Toss to coat evenly.
Roast in the preheated oven for 25 to 30 minutes, or until the tomatoes are deeply blistered and bursting, and the garlic is soft and golden.
While the tomatoes roast, bring a large pot of salted water to a boil. Cook the penne pasta according to package instructions until al dente. Reserve 1/2 cup of the starchy pasta water before draining.
Transfer the roasted tomatoes, soft garlic cloves, and all the pan juices to a blender or food processor. Pulse until the mixture forms a smooth sauce.
Pour the blended tomato sauce into a large skillet over medium-low heat. Stir in the heavy cream and grated Parmesan cheese until heated through.
Add the cooked penne pasta to the skillet, tossing gently to coat the noodles evenly. If the sauce is too thick, splash in the reserved pasta water a little at a time until reaching the desired consistency.
Remove from heat and fold in the fresh basil leaves. Serve immediately, garnished with extra Parmesan cheese and fresh basil.