Cooking for one person can be a bit like working in Kitchen Stadium when Kaga unveils the theme ingredient -- groceries are often sold in large-ish packages and, specially with vegetables and things that can spoil, one is often scrambling to use up the items before the expiry, and to remember or invent dish after dish after dish to contain it.
Whatever in White Sauce and Okonomiyaki are a couple of standby suggestions for doing away with surpluses. Omelettes are also nice things for filling with excess herbs or veggies, and soups can be formed around meats or vegetables or else have a few more added. Fruits can be sprinkled with sugar or drizzled with honey or topped with whipped cream and served as desserts on their own, or crushed and used to garnish other desserts such as puddings, cakes and ice creams. Dairy products like sour cream and unflavored yogurt can often be interchanged with one another in cooking, or switched out for other liquid dairy items like milk or cream as part of a recipe. Nuts can be used the way croutons would be in any dish, or employed as a garnish or topping for many kinds of food, both sweet and savory.