In a bowl, combine ground lamb, garlic powder, rosemary, thyme, salt, and pepper.
Mix gently with your hands—don’t overwork the meat.
Shape into 4 even-sized burger patties.
Heat a grill pan or skillet over medium-high heat.
Cook patties for 4–5 minutes per side or until desired doneness.
Toast burger buns lightly.
Mix mayo and Dijon mustard, then spread on buns.
Assemble burgers with tomato slices, greens, and hot patties. Serve immediately.