I'm having a dinner party and one of the guests (a work colleague and friend) is a picky eater and quite high maintenance when it comes to food. She greatly enjoys cooking and analyzing meals, even if eating in the work cafeteria. How can I make a picky eater and hobby cook with high expectations feel comfortable at my party? I'm afraid she won't like anything as I am not a superb cook, myself.
It makes me a little sad to read your letter because it sounds like you don't like this person very much and that makes me wonder why you would invite her to dinner in the first place. A dinner PARTY is supposed to be fun. Fun for everyone— even you, the host. If you think that having her there won't be fun for you, leave her off the invite list.
If, however, you are just facing general cooking angst and knowing that a foodie will be sampling your efforts is just compounding your anxiety, remember that enjoying and talking about food doesn't mean she doesn't have good manners. It is incredibly bad taste (pun intended) to be anything but complimentary of someone's clearly well-intentioned efforts in the kitchen, especially when you're a guest in their home.
So basically what I'm telling you is you should serve what you want, cook any way you want, and it's her job as your guest to celebrate you for it. If the basis of her pickiness is food allergies or other issues, that's another story and something you can work with her to accommodate, but it sounds like she's just plain ole' particular.
One more thing: you need to give her the benefit of the doubt. If you're already expecting problems from her, you may just start to imagine situations that aren't real. If she grimaces for a moment at dinner, it's not about the food; she probably just knocked her knee. If she whispers to the person sitting next to her, she's probably just sharing some office gossip. Have confidence in your meal and your guests will love it even more.