Preheat Oven To 200. In Large Mixing Bowl, Mix Together Pork, Diced Onion, Garlic, Salt, Pepper, Vinegar, Sugar And Paprika. Form Mixture Into Small Round Patties. In Large Frying Pan, Fry Patties In Olive Oil Until Done. Remove From Pan And Keep Warm In Oven. Drain Fat From Pan And Add Butter. Saute The Onion Slices Until Lightly Browned On Both Sides. Remove Patties From Onion And Place An Onion Slice On Top And Serve.