1. Place the shrimp in a bowl. Sprinkle with cayenne, salt, pepper, and thyme. Toss and set aside.

2. Boil the pasta in salted water until al dente. Drain, reserving some of the pasta water.

3. While the pasta is boiling, melt the butter in a large skillet with the olive oil over medium heat.

4. Saute the onoin until soft, 3 to 4 minutes.

5. Add the chopped garlic and red pepper flakes. Stir for 30 seconds and do not let the garlic burn.

6. Add the tomato paste, heavy cream, parmesan and a small pinch of sugar. Stir and continue to cook until blended.

7. Add the shrimp and cook for 2 minutes.

8. Add the pasta and toss; the reserved pasta water may be added to moisten if necessary.

9. Allow the shrimp to finish cooking another 1 to 2 minutes. Do not overcook. Add the parsley. Season to taste with additional salt and pepper, if desired. Remove from the heat, squeeze the lemon over, and serve.