I think I’d choose to impress my grandmother. So I would make:
Appetizer: Ohh this is a hard one. She’s not big on appetizers. But maybe I can experiment on pig feet - it’s one of her favorites.
Entrée: Pork shoulder - since this is a popular cut in our family. I am sure she’ll be blown away by it sous vide. 
Dessert: She’s been spending a lot of time trying to perfect her flan. I would love to show her that it can be done sous vide!
What would be on your menu? And for who? Can be anyone.
I’ve had great success with sous vide creme bruleé. Can be prepared the night before and you just burn the tops just before serving.
Actually, can be prepared months before. Those little jars freeze very well!!! (just have to make sure that the lid is very loose until it’s completely frozen!! 
Haven’t done them yet (need to pick some up) - I think for an appetizer, I’d do bacon wrapped scallops.
Entrée - a nice rib steak. 
Maybe top it with either a blue cheese sauce or some caramelized fried garlic.
Dessert - +1 for creme brûlée - it’s always been my favourite!!! Keep meaning to try making cheesecake in the bath though…heh…one of these days.
Creme broulee, tritip, and ears of corn. My home run combo!
Doesn’t Someone To Be Impressed eat vegetables?
Heh. Since when are veggies impressive?? I think my microwave steamer still does the best job.
If I want to impress someone with veggies, I’d braise some brussels sprouts in bacon grease.
…or char some buttered wedges of cabbage on the BBQ.