1. Combine garam masala and lavender in a small bowl; stir to combine. Set aside.

2. Rinse back and front cavities of turkey under cold running water; pat dry. Season turkey inside and out with salt and pepper. Rub with bacon fat, and sprinkle with spice mixture; rub to coat evenly. Place in a large metal bowl. Cover tightly with plastic wrap, and refrigerate 24 hours or at least overnight.

3. Preheat oven to 425 degrees. Tuck wings under turkey; tie legs together with kitchen twine. Place in a large, heavy roasting pan fitted with a rack. Roast 30 minutes, then reduce temperature to 375 degrees.

4. Continue roasting, basting turkey with pan juices every 30 minutes (add 1/2 cup water if pan becomes dry). Tent with foil after 1 hour. Roast until juices run clear when thigh is pierced, 2 1/2 to 3 hours total. Insert an instant-read thermometer in thickest part of thigh, avoiding the bone. Temperature should reach 180 degrees. Let rest 30 minutes before carving.