Preheat a skillet over medium or bring a grill to medium-high. A light swipe of oil helps the sausage brown and get that irresistible snap.
Add the chicken/turkey sausage and cook 3–4 minutes per side until browned and heated through. If it's uncooked, follow package directions and cook to 165°F internal.
While the sausage finishes, place whole-wheat buns cut-side down on the pan or grill for 30–60 seconds. Lightly crisped buns = elite texture.
Slice onions, wash greens, and stir together the yogurt-mustard sauce if using. Keep it simple or go bold—your call.
Nestle the sausage into the toasted bun. Layer mustard, relish, onions, greens, and anything else you love. Don't overload to the point of collapse—balance matters.
Hot, snappy, and juicy beats lukewarm every time. Add a side of carrot sticks or baked sweet potato fries for the win.