Lydia at The Perfect Pantry once wrote about what she would take to a desert island for her pantry while she was marooned there.
I've been preparing quite a few meals in our mostly un-supplied condo in Hawaii -- an island, though not a desert. I have managed with only a small palate of flavors -- especially compared to the 127 items Lydia admits to having.
A few spices and some vinegar were already in the cupboard, and of course I bought both olive oil and butter. But in the photo you can see the condiments I've been using.
Mustard goes on all the sandwiches we've been eating. It mixes with oil and lemon juice for local tomatoes and lettuce from the small farms over in Waimaia. I coated chicken with it once for pan frying as well. Salsa is good with chips and on a sandwich. Yogurt is a snack, a sauce for fruit, or if plain, a sauce for chicken -- with cucumbers, which grow here and are quite nice.
Ponzu has a lot of possibilities -- I like to have a bottle on hand at home. It's a different flavor for fresh vegetable salad, as well as being good with steak. I bought fresh bok choi, dried shitake mushrooms, and onion -- Hawaiian supermarkets are almost as well-provided as some Oriental groceries back home. I fried the steak and stir fried the vegetables. Along with Ponzu and a little of the water from soaking the mushrooms, I added a little of the vinegar and a packet of sugar. Luckily, some former occupant had taken the sugar from a cafe and left it in the cupboard as well.
That's my desert island cooking!