Juicy bratwurst with tangy mustard on a crusty roll is a high protein, carnivore-approved cookout essential. This German-American family favorite delivers bold, savory flavor at every gathering.
Heat a large skillet over medium-low heat and add butter.
Add sliced onions and a pinch of kosher salt; cook gently for 8–10 minutes, stirring occasionally, until onions are soft and golden.
Push onions to the side of the skillet and add bratwurst sausages to the pan, increasing the heat to medium.
Brown bratwurst sausages evenly, turning every 2–3 minutes, for about 8–10 minutes or until fully cooked with internal temperature reaching 160°F.
Split the crusty rolls, layer with cooked onions, nestle a bratwurst in each, and finish with a generous spoonful of German-style mustard and cracked black pepper. Serve hot.