Step 1

Toast spices in a skillet over medium heat, swirling often, until fragrant, about 2 minutes. Let cool. Working in batches, finely grind mixture in a spice mill. DO AHEAD: Can be made 1 month ahead. Store airtight at room temperature.

Step 2

Toast spices in a skillet over medium heat, swirling often, until fragrant, about 2 minutes. Let cool. Working in batches, finely grind mixture in a spice mill. Sift through a medium-mesh strainer into a small bowl; stir to combine. DO AHEAD: Can be made 1 month ahead. Store airtight at room temperature.

Step 3

Pat turkey dry with paper towels. Rub inside and out with salt; transfer to roasting bag. Stuff turkey with cardamom pods and cumin seeds, then onion, celery, and garlic.

Step 4

Purée all ingredients in a blender. Pour marinade into roasting bag. Smear all over turkey. Tie bag and arrange turkey, breast side down, in a large heavy roasting pan. Refrigerate overnight.

Step 5

Let turkey stand in a bag at room temperature for 1 hour. Turn breast side up. Create steam holes in bag if required by manufacturer's instructions.

Step 6

Preheat oven to 400°. Roast turkey for 30 minutes. Reduce heat to 350°. Roast until an instant-read thermometer inserted into the thickest part of the thigh (puncturing bag with thermometer) registers 160°, about 1 1/2 hours longer. Cut top of bag open, being careful of steam and juices, and pull back over turkey. Roast turkey until breast is deeply browned but not burned and a thermometer inserted into thigh registers 165°, 15–30 minutes longer.

Step 7

Transfer to a platter. Let rest for at least 20 minutes before carving.

Step 8

Meanwhile, strain juices into a large saucepan. Spoon fat from surface. Simmer over medium heat until sauce is reduced to 3 1/2 cups, about 20 minutes.

Step 9

Carve turkey. Serve with accompanying gravy.