Eating on a budget can be challenging, especially when trying to feed your family the best-quality food possible. Planning your grocery list wisely isn’t just about searching for sales or clipping coupons. Think about the hidden dollars and food that gets wasted — sometimes without us even realizing it. I’m talking about leftovers from recipes that once enjoyed front and center stage, only to be cast in the back of the fridge to be forgotten.

Those leftovers needn’t go to waste, even smaller portions. A few leftover meatballs may not make a complete meal for a family of four, but they’re a necessary ingredient for my Shortcut Bolognese Sauce. The sauce comes together quickly — in about the same time it takes for the water to boil and pasta to cook. Mash the meatballs and saute them with some chopped onions and olive oil in a deep skillet. Once the onions are golden, stir in some marinara sauce and let it simmer for 15 to 20 minutes, so the meat can soak up the flavors in the sauce. With minimal effort, you’ve transformed a humble meal into a hearty one by using a few meatballs to bulk up a simple tomato sauce.

You can use this same approach to leftovers using two other staples you probably already cook at least once a week — rice and pasta. A pot of rice one night can be the base for fried rice or Italian rice balls a few days later. Cold plain pasta is perfect for making a quick noodle stir-fry, pasta salad or torta di pasta (an Italian frittata made with pasta, eggs and cheese). Here are a few tasty ideas for tossing together a meal using leftovers from some of my favorite Food Network chefs:

• Cold Rice Salad

• Sesame Shrimp Fried Rice With Cabbage

• Torta di Pasta

Jennifer Perillo is a recipe developer and food writer living in Brooklyn, N.Y. Her recipes and tips for feeding families homemade meals are a regular feature in Working Mother magazine, where she’s the consulting food editor, as well Relish Magazine , Parenting , Kiwi and her blog, In Jennie’s Kitchen.