Few things in a relationship have to be handled with more care than trying figure out how to tell your girlfriend she's an awful cook. Women can be sensitive about certain things, but so can your taste buds. Unless you want to spend a lot of time trying to secretly feed your dog under the table, you're going to need to bite the bullet and tell her the truth. But how do you do it without destroying her? It can be tricky, but planning out how to tell your girlfriend she's and awful cook in advance will definitely help.
Don't be cruel. She may have offended your sense of taste by serving you something you wouldn't eat on a dare. That's still no reason to be needlessly mean to her. She's probably going to be hurt by the mere fact that you're telling her that you don't like her food. If you say something like, "What you do in the kitchen is a crime against food. What the hell are you thinking?" she may end up in hysterics and your relationship will be headed for big trouble. Try something a bit gentler, like maybe pointing out how much you appreciate her trying to cook for you, and make light of the fact that the outcome is not so great. Chances are she's not completely clueless about her lack of powress in the kitchen and if you can both laugh about it, all the better.
Tell her it's okay. If your girlfriend is cooking for you, she's doing so in order to please you on some level. When you tell her that she's a crap cook, she's going to feel like a failure. You've got to assure her that you love her for lots of reasons and that it's okay she's an awful cook. If she feels unloved, her self-esteem is going to fall into the toilet and you're relationship is going right down with it.
Offer to help her in the kitchen. Since her version of "authentic" spaghetti Bolognese is 70 percent cheap hamburger meat poured over fat overcooked noodles doused with powdered parmesan…it's up to you to show her a few pointers. But, even if you're not a gourmet, you know what you like and unless you've got a lot of disposable income, eating out every night can be too expensive and fast food is unhealthy on top of that. So learning how to make home-cooked meals is a must. By offering to work with her in the kitchen, you're showing her that you want to improve the cooking situation together. You guys can try out recipes together and she may also feel better about cooking since you'll be sharing the successes and the failures rather than leaving the whole burden on her.
Praise her. If you've taken the time to help her in the kitchen, at some point she's going to get over the hump and cook something decent. She may still be an awful cook for the most part, but you've got to give her credit for trying and sticking with it. When she finally does produce something edible, shower her with praise. Tell her what you liked about it and the chances are that you'll see her improving that recipe each time she makes it. She may even carry over some of the things she learned to some new dishes.
It's painful, but when things get really bad you've got to come up with a good way to tell your girlfriend that she's an awful cook. The main thing is that you want her to improve. She's not totally beyond redemption, right? Be honest with her and if you're not a jerk about it, it's a good bet that things will slowly improve. And if not…well, ramen noodles aren't so bad, are they?