left: unbaked vegetables ready to go into oven
One type of convenient product I have come to love is the spice or herb blend. I have a "greek seasoning" blend and a "creole seasoning" blend that can be used on almost anything. One example is this easy roasted veggie dish. These are general directions because the dish will vary with what you have on hand, what you like, how much you want to make.
Use fresh vegetables from your refrigerator. Or you could use the stew-type frozen vegetable mixes available in grocery markets for an even easier version. Root vegetables, like potatoes and turnips and onions, make fine roasting fodder. Bell peppers of any color, leeks, squash, all are good. The cruciferous vegetables, like cabbage and broccoli, may not fare as well but could work if the dish is covered long enough to get them steamed. Corn could make a great addition (frozen or fresh).
Estimate how many veggies you'll need based on how many will be eating and how big a pan you'll be using. You'll want the veggies to make a layer that is not too thick so they will all cook evenly. Wash and cut the vegetables into bite-size chunks. Leave skins on potatoes.
left: roasted vegetables ready to eat
Pile the vegetables into a shallow roasting dish or casserole. Sprinkle a couple of tablespoons (or more, depending on how many there are, you want a very light coating) of olive oil on top, and a generous amount of greek seasoning mix on top of that (or try another seasoning mix that goes well with vegetables, like Italian). Mix lightly and cover the pan (with a lid or with foil). Bake at 350 degrees for 30-45 minutes, stirring two or three times. Remove lid or foil and let cook 5 - 10 minutes uncovered.