IMO the most efficient food plants are the ones you can preserve in a manner that you will use throughout the year. Do you can? Or have a dehydrator?
Tomatoes can be canned, frozen, or dehydrated (sun-dried tomatoes!). You can make them into juice, paste, sauce, or salsa, and can that. The thing about tomatoes is they take up a good deal of space, generally prefer full sun, and you need rather a lot of them if you're cooking them down into something like sauce.
If you grow a ton of onions & garlic one year, you can mince and dehydrate them (then grind into powder if you wish), and you'll be set for a good while. You probably won't need to grow those the following year.
Things like zucchini or yellow squash grow in abundance, but don't preserve particularly well. If you grow those, you'll be eating squash all the time, for a very short period of time, or it will go to waste.
Sweet corn can be frozen, or canned, but I think frozen tastes better. Strawberries can be frozen to use as a dessert topping or for baking, or you can cook them into jam, and can that.
You can grow beans and can those with tomato juice & chili spices for home canned chili beans, or make a "baked beans" type of sauce and can them in that. Green beans can well, and freeze, too. Same for peas.
You can freeze potatoes for hash browns, or can them. Carrots can well, too.
Do you have the space to plant a fruit tree or two? Apples grow well in the midwest, and you can make (and can, or freeze) homemade apple sauce. If you want to get really creative, make some apple cider vinegar.
If you're far enough south to grow a peach tree, you can get a boatload of fruit to make jam or pie filling.
Lettuces don't preserve very well, so you're best off planting one or two every couple of weeks throughout the growing season, in an attempt to have one plant grown to cutting size about the time you finish consuming the last one you cut.
If you have the inclination to try fermenting as a preservation method, you can grow cabbage and make sauerkraut.
I think you can blanch & freeze broccoli, I'm not sure about cauliflower (I don't like either of these, so that's why I don't know much about them).
Chili peppers (ancho, serrano, guajillo, jalapeno) can be made into sauces/salsas, or dehydrated & ground to powder for use in cooking.