Use to make Maialino chef Nick Anderer's Pollo Alla Diavola.
Preheat oven to 500 degrees.
Using a sharp knife, split peppers lengthwise, but do not cut all the way through peppers, leaving them whole. Place in a large bowl and drizzle with olive oil; toss to combine. Transfer to a baking sheet and roast until slightly softened, about 10 minutes. Transfer to a large bowl; set aside.
Combine vinegar, 1 cup water, salt, sugar, garlic, peppercorns, thyme, and bay leaf in a medium saucepan. Bring to a boil over medium-high heat. Pour vinegar mixture over roasted peppers and let stand at room temperature until cool. Cover and refrigerate at least 3 days and up to 4 months before using. Bring to room temperature before eating.