Combine the butter, onion, and sugar in a pan set over medium-
low heat. Cook the onions, covered, for about 30 minutes, stirring
every 5 minutes; they should be nicely caramelized. Transfer the
onions to a bowl, cool to room temperature, then refrigerate until
well chilled, at least 3 hours.
Preheat the oven to 425 F. Grease or line a baking sheet with
Combine the flour, baking powder, and salt. Work the butter into
the flour until the mixture is unevenly crumbly.
Toss in the chives and caramelized onions.
Cut in the starter until the dough becomes cohesive. Turn the
dough out onto a lightly floured surface and use a bench knife or
bowl scraper to fold it over on itself five or six times, until it comes
Pat the dough into a 1 inch-thick disk.
Use a sharp 2 1/2 inch biscuit cutter to cut rounds. Pat the scraps
together, and cut additional biscuits.