In a medium-sized pot on medium heat, heat the tallow or olive oil and sauté the onions and garlic until translucent, around 5 minutes.
Add the cumin, paprika and 1 tsp salt, then add the diced red peppers. Sauté for another 5 minutes and add the ground beef.
Reduce the heat to medium-low and break up the ground beef as it cooks with a wooden spoon.
Once the ground beef is partially cooked, add the potatoes, beef broth and remaining salt. Let this mixture simmer for 30 minutes, until liquid is reduced by half, stirring occasionally. If the liquid has reduced too much add some more water, if it has not reduced enough cook for another 5-10 minutes.
After 30 minutes, the cubed potatoes and beef should be cooked, and the broth reduced by half. (For juicier empanadas, don’t reduce the liquid as much. The broth should reduce to about 1/2 an inch over the rest of the ingredients.)
Turn the heat off and add the currants. Make the arrowroot slurry, mixing until smooth, then stir into the ingredients in the pot.
Season to taste and set aside in the fridge to cool down. The filling may be stored in the fridge for up to 14 days.