1
Sauté diced onion in butter and olive oil.
2
Add flour, then whisk in chicken broth and heavy cream.
3
Season with Italian herbs, garlic powder, black pepper, chili flakes, and salt.
4
Stir in freshly grated Parmesan, lemon zest, and a splash of lemon juice.
5
Toss with cooked spaghetti, adding pasta water until the sauce becomes silky.
6
Finish with parsley and extra Parmesan.