Bring a large pot of salted water to a boil and cook the penne per the package directions. Drain, reserving about a cup of the pasta cooking water.
In a large skillet, heat the olive oil over medium heat. Add the garlic and cook for 30 seconds. Add the lemon juice, half the lemon zest, ricotta cheese, and Parmesan and cook until melted and warm, 2-3 minutes. Stir in the peas and cooked pasta. Add some of the pasta water if the sauce is too dry.
Season to taste with salt and pepper. Garnish with basil and the rest of the lemon zest.