Important tips: Don’t wash basil until ready to use. Use small to medium garlic cloves to avoid overpowering. The pasta water is essential for a creamy sauce. Taste and adjust seasoning. Store leftover pesto in a jar with a thin layer of olive oil on top; keeps in fridge for a week. Freeze pesto in ice cube trays for instant dinners. For dairy-free, omit Parmesan and add nutritional yeast. For nut-free, use toasted sunflower seeds.