Let the lamb sit at room temperature first.
This takes about 30 minutes before cooking.
Pat the meat dry with paper towels thoroughly.
Season generously with salt and pepper on all sides.
Mix breadcrumbs with rosemary, thyme, and garlic together.
Add melted butter and olive oil to the mixture.
Stir until everything is evenly combined and moistened.
The mixture should hold together when pressed lightly.
Heat a large skillet over high heat until hot.
Sear the lamb racks fat-side down for 2 minutes.
This creates a beautiful golden brown crust outside.
Turn and sear all other sides quickly too.
Brush Dijon mustard generously over the lamb racks.
This helps the herb crust stick perfectly to meat.
Don't skip this step—it adds wonderful flavor too.
Press the herb mixture firmly onto the lamb.
Cover the top and sides completely with mixture.
Pat it down so it adheres well to surface.
Roast at 450°F for about 20-25 minutes total.
Check internal temperature with your meat thermometer carefully.
Aim for 125°F for perfect medium-rare doneness.
Let the lamb rest for 10 minutes after roasting.
This allows juices to redistribute throughout the meat.
Slice between the bones and serve immediately afterward.