2 pork tenderloin, about 3/4-lb each 
2 teaspoons ground cumin 
1 teaspoon paprika 
1/2 teaspoon salt 
1/4 teaspoon pepper 
2 tablespoons olive oil 
1/2 cup chopped onion 
2 cloves garlic, minced 
1/4 cup Madeira wine 
1/4 cup water 
1 tablespoon red wine vinegar 
2 tablespoons butter 
2 tablespoons chopped cilantro or parsley, if desired 

Cut each tenderloin into 8 slices (partially freezing the tenderloins will make slicing easier). Sprinkle the pork with cumin paprika, salt, and pepper. Saute pork in oil for 6 to 8 minutes on each side, or until browned and cooked through. Transfer to serving platter and keep warm.

Drain off fat from skillet; add the chopped onion and garlic and saute 3 or 4 minutes or until wilted and just lightly browned. Add Madeira, water, and vinegar, stirring well. Bring to a boil, reduce heat, and simmer until liquid is reduced to about 1/3 to 1/2 cup. Add butter and stir until melted. Pour sauce over medallions and garnish with cilantro or parsley if desired.
Serves 4.