01 - Bring 4 cups water and 1 teaspoon salt to a boil in a medium saucepan. Add orzo and cook according to package instructions (about 8-10 minutes) until al dente. Drain well.
02 - While orzo drains, melt butter and olive oil in the same saucepan over medium heat. If using garlic, add minced clove and sauté for 30 seconds until fragrant.
03 - Return drained orzo to saucepan. Add lemon zest, lemon juice, Parmesan, black pepper, and parsley. If using peas, stir them in now.
04 - Toss everything together until orzo is creamy and well coated. Season with additional salt and pepper to taste.
05 - Serve warm, garnished with extra parsley and lemon zest if desired.