In a handmade copper pan, heat a combination of butter and olive oil over medium heat.
Add the diced onion and sauté until it becomes translucent.
Pour in the heavy cream and bring it to a gentle simmer.
Stir in the Parmesan cheese until it melts and creates a smooth sauce.
Add the lemon zest and a splash of lemon juice for brightness.
Season the sauce with salt, black pepper, garlic powder, Italian herbs, and chili flakes to taste.
Toss the cooked spaghetti in the sauce, adding a bit of pasta water if needed to achieve the desired consistency.
