It was delicious. Who would ever have guessed it had been in my freezer for, like, 5 years?
Here's what I did. I took it out of the freezer and let it defrost in a bucket of brine (1/2 cup-ish diamond crystal salt to 1 quart water) overnight. Also cut up and threw in a few oranges that were starting to look wrinkled, a few sprigs rosemary and some bay leaves. This afternoon I removed it from the brine, rinsed it and put it in a heavy roasting pan. Surrounded by (and stuffed with) chunks of carrot, parsnip and leeks plus a few peeled cloves of garlic. Threw in a few sprigs rosemary, a sprinkle of herbs de Provence and grind of pepper. Tightly covered and put in 500o oven for 10 minutes. Then turned down the heat to 300o and let it roast, undisturbed, for 3-1/2 hours. Removed the cover and let it finish roasting uncovered for another 1-1/2 hours. It was absolutely fantastic - collapsing under its own weight and with no freezer taste whatsoever.
I served it with some of the veggies from the pan (which were extremely soft), braised kale, roasted butternut squash and a salad made with mixed greens, red onion, chunks of papaya and pomegranate seeds. Dressed with salt, pepper, olive oil and pomegranate molasses.
Glad I didn't throw that baby out.