Unlike domesticated geese, which typically go to market at around 9 weeks old, wild geese can hang out for a decade or two before they make it to the table, basically eliminating high-heat roasting from the list of viable cooking methods. That's where the slow cooker comes in. Like a culinary equalizer, the slow cooker stews the goose to tenderness every time, regardless of age -- five to nine hours in moist heat does that to meat. Sear the goose after slow-cooking for crisp skin.
Take the goose out of the refrigerator for about 30 minutes to take the chill off it. Trim any fat hanging from it; goose has enough fat under its skin to make additional fat extraneous. Examine the goose for any shotgun pellets missed during cleaning.
Prick the skin of the breasts and thighs using a paring knife. Add the vegetables, herbs and spices in an even layer in the bottom of the slow cooker. Lay the thighs and breasts skin-side up on the vegetables.
Fit the legs into the spaces around the thighs and breasts, or, if needed, on top of them. Cover the slow cooker. Reserve the wings for stock.
Set the slow cooker to High for a five-hour cooking time or Low for a nine-hour cooking time. Add fresh herbs to the slow cooker during the last 30 minutes to one hour of cooking.
Take the goose from the slow cooker after its set cooking time. The cooker will hold the goose warm until you can get to it, but don't allow to stand for more than one hour.
Pat the breasts, thighs and legs dry. Add about 1 tablespoon of the goose fat from the slow cooker to a skillet. Heat the fat over medium-high heat for several minutes.
Lay the breasts skin-side down in the skillet. Fry the breasts until the skin crisps, about 5 minutes. Turn the breasts over and fry them for about 3 minutes. Set the breasts aside.
Fry the thighs and legs until the skin crisps. Strain the warm goose fat in the slow cooker through a mesh strainer lined with three or four layers of cheesecloth. Reserve the goose fat in the refrigerator for use in any preparation where a frying fat is needed.
Add 1 to 2 tablespoons of goose fat to the skillet after you sear the breasts, legs and thighs and set the heat to medium. Sprinkle the flour over the fat.
Cook the flour in the fat until it browns. Add the duck or chicken stock to the skillet. Whisk the stock vigorously until the flour breaks up.
Simmer the gravy for 10 to 12 minutes, whisking frequently. Season the gravy to taste with salt and pepper and finish it with a few tablespoons of heavy cream.