Heat the olive oil and unsalted butter in a large sauté pan. Sauté the sausage until it is lightly browned. Add garlic, red pepper flakes, flour, and cook for a minute to slightly soften the garlic.
Add the stock and bring it to a boil.
Reduce the stock mixture until only about ½ cup of liquid remains. The mixture will be a sauce consistency. Whisk in the 1-tablespoon of the butter to the reduced sauce. (While the stock/sausage mixture is reducing cook the pasta).
Add tomatoes, drained kale, and basil. Add the well-drained pasta to the meat mixture and cook for an additional minute or two allowing the sauce to be absorbed by the pasta.
Add 1 tbsp of butter and 1 cup of cheese and sprinkle the remaining cheese on top of the pasta.