Pickled onions

I order the barbacoa tacos at Nada for the pickled onions alone. When I was planning my most recent taco night, I decided to see how difficult it would be to make a batch of my own. Turns out, not hard at all. I based mine off a few recipes, most notably, David Lebovitz's recipe.

Pickled Onions
1 to 2 cups white vinegar
3 to 4 Tablespoons sugar
pinch of salt
1 bay leaf
generous shake of red pepper flakes
whole black peppercorns
1 to 2 large red onions, peeled, and thinly sliced into rings

In a small, non-reactive saucepan, heat the vinegar, sugar, salt and seasonings until boiling. Add the onion slices and lower heat, simmering gently for a minute. Remove from heat and let cool completely. Transfer the onions and the liquid into a glass jar and refrigerate until ready to use. The onions will keep for several months.