Using leftovers is important for any food budget. If you plan in advance to use the leftovers you create, you won't waste food and can likely double how long your food lasts. Also, by using the leftovers to make quick meals, you can save time on busy days.
Using leftovers in the most budget-friendly way means that you should know what you're cooking, when you're cooking it, how to store it best, and what you will do with the leftovers and when. So, if you're making pizza tonight, you might want to save some of the sauce, roll up leftover slices and have pizza dip tomorrow for lunch.
Some things make great leftovers just as they are. But the truth is, if you transform your leftovers based on a plan, you can make meals that do not seem like leftovers at all. For example, if you make rice tonight for dinner, it's best eaten like it is because it's fresh, fluffy, and delicious. Tomorrow it will be hard and will not have the same texture. But the new texture is perfect for stir-fry. Throw your leftover rice in a pan with a bunch of veggies, a squirt of sesame oil, shredded leftover chicken and it'll seem as if this is a brand-new meal.
The foods that you want to be leftovers are foods that improve their flavor and texture over time. This is true of soups, stews and it's also true of spicy dishes which get spicier with time. If you know your ingredients, you can know exactly how to reuse them when you cook with them.
When you store your leftovers, the best way to ensure that you're going to use them is to label them. For example, if you're saving rice for stir-fry, put on the label, "rice for stir-fry". Include the date so that you know when you need to use it by.
Each type of leftover has a storage method. For example, when it comes to beans and grains you should freeze them. This works great for beans since it's less expensive to make beans yourself than buy them in a can. But, if stored incorrectly they can become mushy. Drain them and rinse them before storing. Then you can simply take them out of the freezer and toss into your recipes.
Leftovers vegetables are almost always good in soup. Leftover broccoli can easily become a delightful creamed soup. Just throw the broccoli in a blender with almond milk, butter, and use leftover cooked onions to give it even more flavor. Add salt and pepper to taste. Heat on the stovetop, grab some bread or rolls and enjoy a fast meal.
Another great thing to do with almost any type of leftovers is to combine them into a wrap. Get a flour tortilla (or lettuce leaves) and add leftover meat, veggies, rice, beans, add some salsa, you've got an easy meal - all from leftovers.
Casseroles are one-pan dishes that just need a bit of creativity. Mixing any type of starch, protein, veggies, and cheese, with a crunchy topping of breadcrumbs will almost always be good.
If you want to do better with leftovers, think of them during your meal planning. Think about what you're cooking, and plan for using the leftovers in the meal the following evening or for a quick take-along lunch. If you plan it right, you can cook once, then eat two or three times - saving time, electricity, and your sanity.