For sauce: Mix dry ingredients. Add vinegar, water and mix. Bring to full boil and add stick of butter and continue to cook until butter melts. This makes 1 Pint of the Sauce.
Soak venison in water, vinegar and salt for 4−5 hours. Remove and wipe dry. Sprinkle lightly with pepper and brush with sauce. Add onion and enough water to cover bottom of covered roaster.
Bake in 325F oven the first hour; then lower heat to 275 F for an additional 3 hours.