Toasting spices unlocks their potency and gives their flavor its fullest expression.
Pre-ground spices are pretty much worthless: the volatile compounds that give them their flavor are released (and begin to dissipate) as soon as they’re ground. While their convenience is seductive, pre-ground spices contribute very little, flavor wise; in order to make your food taste like anything, you have to add enough insipid powder to make it downright gritty.
There are exceptions, of course: it’s not practical to grind cinnamon yourself. But in most cases, toasting and grinding your own is the way to go.
Don’t be intimidated: it only takes a few more minutes than opening a jar. Plus, buying spices in bulk saves you money. Use a heavy skillet (preferably cast iron, definitely not non-stick). Add your spices when the skillet is still cold, and shake it gently from time to time. Your spices are ready when they’re fragrant; if you wait until they’re smoking, they may scorch. When toasting seeds, like cumin and coriander (two of my favorites, and stalwarts in my kitchen), you may hear them popping when they’re done. As with anything else, spices will toast up much faster over gas heat than electric. Because the difference between beautifully toasted and burnt is a matter of seconds, it’s important to stay vigilant, especially during the last minute.
After your spices are toasted you can grind them by hand in a mortar and pestle or a suribachi (a Japanese mortar and pestle, the very best), or use a coffee grinder. Most people recommend using separate grinders for spices and coffee. I used to do this, until my spice grinder gave up the ghost. Now, I use the same one. I’m not a purist.
Workhorse Spice Blend
2 T cumin seeds, toasted and ground
1 T coriander seeds, toasted and ground
1 t cinnamon
1 t dried oregano
½ t cayenne
I use this combination of spices in pretty much everything. You can use it to flavor soups, stews, and sautéed vegetables. You can use it as a rub for grilled or seared meats. You can up the cinnamon for a North African-inspired flavor, add a little chipotle for Mexican food, or add toasted sesame seeds and chopped hazelnuts or pistachios for a homemade take on duqqa, a dry condiment served with bread and olive oil.