Bring a large pot of salted water to a boil. Cook the pasta according to the package instructions. Do not drain.
Meanwhile, halve the cherry tomatoes; set aside.
In a large skillet, warm the olive oil and garlic over medium-low heat. Cook the garlic for only 30 seconds.
Add the tomatoes. Season with salt and pepper. Simmer, stirring occasionally, until the tomatoes collapse and release their juice, about 5-7 minutes. Then add the cold butter.
Continue to cook until the sauce thickens (I use this time to thinly slice the basil into ribbons). Add a handful of ground Parmesan cheese to taste, and stir will to combine.
With a fine mesh strainer, scoop out the pasta and add it directly to the pan. It’s OK if some of the water clings to the pasta. Stir well to coat. Note: if the sauce is too thick, add a splash of the pasta cooking water to loosen the texture.
Add the basil.
Taste, and season with more salt and pepper if needed.
Portion the penne pasta into bowls. Garnish with extra Parmesan cheese, black pepper and a drizzle of olive oil to serve.