Not only are they great to snack on when you just need something crunchy, but they're a tasty addition to pretty much any baked good. Plus, sometimes you can even grind it up really well and add it to flour if you're running a little short for your recipe.
Capers come in a pickling solution, so they keep practically forever in the refrigerator. Do not make Chicken Picatta without them, and they add a great zing to pasta or potato salads.
Not only do you never know when you might need to whip up a chocolate ganache, but there's really no substitute for being able to add cream to pasta sauce for an amazing depth of flavor. An unopened carton can last a surprisingly long time (I've managed to keep it for a month at least before, though don't count on that during the summer.)
Dark Chocolate Chips
Like with the cream above, you never know when you might need to whip up a quick batch of ganache to use as frosting, cookie or ice cream topping, or truffle center, not to mention nothing is better in chocolate chip cookies than Ghiradelli's 60% cocoa chocolate chips. Nathan also eats these frozen by the handful, so I try to have them on hand for a quick chocolate fix.
Especially during grilling season, I prefer this to sprinkle on grilling meat or seafood because the bigger flakes adhere better and last through the whole cooking process better.
You really can't make any sauces taste authentically Thai without lemongrass. It also adds a really nice flavor to stir fry, and don't even think about Tom Yum Soup without it. Usually you can find it in the produce section of the grocery store, but luckily we can get it already chopped and frozen from a local Asian grocery store.
Fresh lemon or lime juice is much more flavorful than bottled. There are a ton of ways to use slices, zest, or the juice of lemon or lime. Just to name a few, we throw them in with fish and vegetables on the grill, add them to pitchers of water when we're sitting outside on a hot day, use lemons in Chicken Picatta, and limes with black beans or mango salsa. They keep very well in the fridge so you really just need to use them within a week or two of buying them. (I do have bottled juice as well, but only as a backup if I need more than I can get from the fresh lemons or limes I have on hand except when it comes to lemonade-just use bottled juice and throw in some lemon slices.)
Good Olive Oil
While it is not cheap, there are some things that justify using a really good olive oil. For one, any homemade salad dressing tastes much more amazing with good olive oil. My favorite is hojiblanca, which has a peppery bite to it. Yum!
If you keep it either completely dry (wrapped in paper towels) or with the stems in water, parsley will stay fresh a few weeks. Fresh parsley really makes a difference in everything from lemon vinaigrette to pasta salads, chicken and fish dishes.
Pine nuts can be pretty expensive, but you don't have to use a lot in any dish. One cup of pine nuts can go a very long way (I store unused pine nuts in the freezer). First of all, you absolutely cannot beat the taste of fresh pesto. There has never been a jar of pesto that tastes even half as good as homemade. It's really easy, and you can freeze it into multiple containers so you have enough for just one meal at a time. (Freezing the pesto doesn't change the taste at all.) Also, pine nuts are really great as a substitute for regular nuts in cookies or toasted and thrown in a salad.
There are two dishes we make relatively often that require shallots. One I've mentioned recently, and the other is a citrus salad with a warm vinaigrette from the In the Kitchen with Rosie cookbook. Even if you don't have a go-to recipe that calls for shallots, however, I find myself using them when I make fish or even vegetables like spinach or green beans. They have a slightly sweeter, more delicate flavor than an onion. That difference is really noticable, which is why I don't just use onions instead every time.
Sparkling Water in cans
I've started drinking La Croix instead of soda for those times when I just really need the fizzy burn, and I've noticed how handy it is to have sparkling water on hand for other things. Flavored or unflavored, you can use it to make pretty much every mixed drink tastier. Plus it keeps for practically forever as long as it's unopened. Sometimes I substitute this in for the water in lemonade, and it's delicious. But best yet, Pimm's Cup is my current summer afternoon adult beverage of choice, and you can't make it without it.
Images (via flickr) from left to right, beginning in top left corner:Roasted California Almonds; Capers; cream is good; Blueberry Papaya Cucumber Juice and Chocolate Cake with Ganache;
kosher salt; Olive oil, lemon, both Golden; Lemongrass Stalks; Olive Oil;
Parsley; Toasted Pine Nuts; Mixed Shallots; La Croix