In a large skillet, sauté the onion in olive oil. After 10 minutes, add the red bell pepper and continue to sauté.
Add the tomato and garlic and continue to sauté until soft.
Let the mixture cool, and then add all of the Olives as well as the paprika and vinegar. Salt and pepper to taste.
Put the yeast and warm water in a large bowl, and stir to mix. When it becomes foamy, after about 20 minutes, whisk in butter, oil, 1 beaten egg, saffron, minced black Hojiblanca olives and salt. Add flour and knead until smooth.
Cut in two, and place in a greased bowl. Cover and set aside.
Roll out the dough to ¼ inch thick on a lightly floured work surface.
Cut out 6-inch rounds of dough. Add some Sofrito filling to each empanada and fold the dough over in half to enclose the filling. Use a fork to press and seal the edges closed. Refrigerate the uncooked empanadas on a baking sheet for up to 3 hours or until firm.
Place on parchment-lined baking sheets and brush the top of empanadas with 1 beaten egg.
Bake for 40 minutes at 350ºF or until golden brown.