Boil water and heavily salt it. Add pasta of your choice.
Over medium heat, add olive oil and butter. Sauté shallots and garlic for 1 minute.
Add lemon zest and crushed red pepper flakes if desired. Stir for 1 minute.
Add lemon juice, heavy whipping cream, and season with salt. Stir.
Using tongs, add al dente pasta directly into the sauce along with ½ to 1 cup starchy pasta water. Cook over medium heat until the sauce thickens and pasta and sauce are incorporated (usually 1 minute).
Garnish with fresh lemon slices, grated parmesan, and cracked black pepper.
