I usually cook in batches, partly because I like having leftovers for lunches and partly because I am my mother's daughter and thus culturally/genetically predisposed to making way too much food for any occasion. After a couple meals of the same food, however, I get bored and want something new. These are a few of my methods for giving my leftovers a makeover so they seem fresh again.
1. STUFFED PEPPERS
I think stuffed peppers are the perfect way to use up grain and bean leftovers. The peppers have a bold enough flavor that they make the leftovers taste like a completely new meal. To prepare, cut the tops off of bell peppers, pull out the seeds, cram the leftovers inside, and bake in a 350-375 degree oven until heated through.
I like to make temaki (sushi cones) out of vegetable leftovers (pictured is spaghetti squash and kale). A sheet of nori adds flavor and minerals, and also turns any food into finger food. To assemble, spread leftovers diagonally across a sheet of nori, and roll it into a cone. Dampen the edge and press it down to help the roll hold together.
This one is pretty obvious, but lots of leftover dinners make good burrito fillings.
4. BAKED POTATOES
Lentils and chili are two of my favorite baked potato toppings.
5. PET FOOD
If all else fails, most dogs are happy to help use up leftovers. My dog Jasper is a vegetable fiend and in addition to leftovers, will gladly compost my carrot tops, zucchini ends, and any green beans I'm willing to throw his way. I figure as long as I avoid giving him anything that might be toxic to dogs, like onions and chocolate, eating some vegan leftovers is a healthy addition to his diet, and can save me a little money on dog food.