Here's an easy idea for newbie and regular cooks alike. It's a great and healthy way to use up some leftovers, and you can change it any way you want.
Wash and slice some bell peppers in half (width-wise! As in, don't slice through or next to the stalk. The stalk should be whole on one half) and remove the seeds and the thin, light parts that stick out. Roast each half on an open flame on the stove, using tongs to rotate them once they get a bit black.
Then warm up and some leftover vegetable, meat or potato dish and mash it a little if it is too big or solid. (I ended up using some leftover cauliflower-tomato dish Fill each half with some filling, place them in a baking dish, squeeze some lemon on top and bake. The bell peppers should become quite soft and easy to cut through, but still sturdy.