Cut meat and fat into strips, about 1/2"x1/2"x4" long or longer. Chill thoroughly.
Toast sage leaves in saute pan on low heat until fragrant with grey spots. Chiffonade.
Grind black peppercorns thoroughly.
Toss meat and fat with spices and grind thought 3/16" grinder die. Mix with ice until thoroughly incorporated and rest overnight.
Mix sausage and test to confirm emulsion: it should appear shaggy, feel sticky, and try to form a single mass. Fry a small amount in a dry pan: it should render very little fat and have a slightly firm, juicy texture.
If smoking, stuff into sausage sacks and cold smoke up to 6 hours. Refrigerate, slice or patty, and fry to serve.
Notes
Milk solids are optional here: fresh meat of good quality will bind correctly if you keep it cold and let it rest overnight. Milk solids produce a firmer, bouncier product.