Black PepperPepper is one of the last things you add to a dish, so its flavor has a big impact. Always grind your own.
The upgrade: Tellicherry black peppercorns ($4 for a four-ounce bag, penzeys.com).
ButterUse creamy European-style butter on the rare occasions you use butter for cooking. Buy unsalted to control the sodium.
The upgrade: Organic Valley, Horizon Organic, or Land O' Lakes Ultra Creamy Butter ($3 to $3.50 for eight ounces, in supermarkets).
Canned TomatoesOrganic tomatoes come in enamel-lined cans, so there's no metallic taste―just a fresh, natural flavor.
The upgrade: Muir Glen Organic tomatoes ($1.50 for 14.5 ounces, in most supermarkets and health-food stores).
Chicken BrothBroth from bouillon cubes is overly salty and suspiciously yellow. Low-fat, low-sodium broth is ideal.
The upgrade: Swanson Natural Goodness 100% Fat Free ($3 for 32 ounces, in supermarkets).
EggsSpring for organic eggs from free-range chickens. The yolks are bright yellow-orange, not a muted yellow, and the taste is full, rich, and downright eggy.
The upgrade: Greenbrier or Trader Joe's ($2.50 to $3.50 a dozen, at health-food stores or Trader Joe's, traderjoes.com for store locations).
Extra-Virgin Olive OilThere is a huge difference in quality between the big-brand varieties and oils made by small producers. A flavorful extra-virgin olive oil can transform a simple salad into something spectacular.
The upgrade: Lucini Italia ($19 for 500 milliliters, lucini.com) or Bertolli Gentile ($6 for 500 milliliters, in supermarkets).
ParmesanBypass the canned version. The best-tasting Parmesan is from a specific region in Italy and has the Parmigiano-Reggiano stamp on its rind.
The upgrade: Authentic Parmigiano-Reggiano ($9 to $18 a pound).
Peanut ButterThe kids' stuff is loaded with sugar. The natural kind contains only peanuts and salt.
The upgrade: Smucker's Natural Creamy Peanut Butter ($3 for 16 ounces, in supermarkets).
SaltKosher and sea salt are clean-tasting and easy to control with your fingers.
The upgrade: Maldon Sea Salt ($7 for 8.5 ounces, thespicehouse.com) or Diamond Crystal Kosher Salt ($3 for three pounds, in supermarkets, or call 800-428-4244).
TunaItalian-style light-meat tuna packed in olive oil delivers a double dose of good fats. It has more calories than the all-white-meat, water-packed kind, but it doesn't need a lot of mayo when made into tuna salad.
The upgrade: Genova ($2 for six ounces, in supermarkets).
VanillaUse pure (not imitation) vanilla extract and you'll be wowed by its complex, heady perfume.
The upgrade: Nielsen-Massey Madagascar Bourbon Pure Vanilla Extract ($20 for eight ounces, kingarthurflour.com) or McCormick Pure Vanilla Extract ($7 for four ounces, in supermarkets).