One day ahead: Put uncooked oats in food processor and pulse 4 or 5 times (or put oats in plastic bag and crush with rolling pin). Put sausage and water in large saucepan, add onion, peppercorns and bay leaf; simmer 1 hour, breaking sausage into small pieces. Strain sausage; reserving liquid. Discard peppercorns and bay leaf; set meat aside.
Measure 3 cups reserved liquid (add more water if necessary) and put into large saucepan. Add salt, mace and cayenne; bring to boil. Add oats; stir and cook 5 minutes (mixture will be very thick). Cover and let stand 5 minutes.
Add cooked sausage and onion mixture; stir until well-blended. Pour into 9-by-5-inch loaf pan, pressing down firmly. Refrigerate overnight.
To prepare: Slice goetta into 1/4 to 3/8-inch slices (3 per serving). Heat non-stick skillet over medium-high heat (no oil needed) and brown goetta slices well on both sides. For traditional skillet, spray with vegetable oil spray and add 1 teaspoon vegetable oil for every 6 slices goetta. Heat over medium-high heat and brown well.
Per 2 ounce rehabbed goetta serving: 180 calories and 5 grams fat (restaurant or store-bought goetta contains 396 calories and 33 fat grams).
Recipe Rehab is compiled by Karen Weber, Pat Streicher and Ellen Illig, registered dietitians at the Jewish Hospital Cholesterol Center, Cincinnati, Oh