I'm almost always pretty stocked on groceries, so I usually do one of two things.
First meal would be to bake some chicken in the oven (usually frozen, and usually with bbq sauce and a little soy and garlic). I also will roast some potatoes in the oven in a huge baking dish with olive oil and salt and pepper, and when they're about halfway done I'll also pop in another pan of veggies to roast (usually with a little balsamic/s&p/lemon): any combo of peppers, cauliflower, carrots, tomatoes, etc... I'll throw some basil on at the end. Once those things go in the oven I make a green salad. Serve with dressings and bread, if I have bread. It takes about 15 minutes to prep and an hour to cook. When it's all ready I just pull it out and serve.
Other meal I have started making for my vegetarian in-laws is to take one large eggplant, layer it in a big baking dish with thin tomato slices, salt and pepper and garlic, olive oil, some red peppers, and lots of oregano and basil and parsley. I stack these things and when it's all assembled I usually add some tomato sauce (jarred, canned, or homemade) to the pan in the empty areas - there are not many empty areas though, and you can skip this step since the veggies juice a bit in the baking process. After baking for 40 minutes or so, I top the stacks with fresh mozzarella and bake another 10 minutes to brown it. Serve over pasta and with a big green salad and crusty bread.
I like to make meals that I can prep for a short period, get going, walk away and attend to again 10 minutes before we eat.