Place the garlic cloves in a 1-quart heavy-bottomed saucepan and add enough olive oil to cover by 1 inch. Crack the peppercorns using a mortar and pestle; or lay the peppercorns on a sturdy work surface, cover with a clean kitchen towel, and give the peppercorns several swift whacks until most are split open. Add the cracked peppercorns and red pepper flakes, if using, to the oil and place the pan over very low heat.

After about 5 minutes you’ll see the oil begin to bubble. Let the oil and garlic simmer gently for 10 to 15 minutes, uncovered. Don’t let the oil simmer too briskly or the garlic might burst (I once found a few cloves clinging to my kitchen ceiling). When the garlic is tender, remove the pan from the stove and add the crumbled herbes de Provence, if using. Let the garlic confit cool and, after you’ve used what you need for that day, store the rest in the refrigerator, in tightly covered containers, to use throughout the week. For best flavor and ease of use, bring the oil to room temperature before using.