Put the butter in a large skillet over medium heat. When it melts and foams, add the onions and sprinkle with a little salt. Cook, stirring frequently, until they’re soft, about 3 minutes.
Raise the heat to medium high and add the peas, panko, and buttermilk powder. Cook, stirring almost constantly, until peas get bright and shiny and crumbs darken a little, 3 to 5 minutes.
Taste and add more salt if you’d like, then stir in the mint. Serve hot or at room temperature.
— Recipe developed by The Bittman Project for Bob’s Red Mill