Heat oil in a heavy pot over medium heat.
Begin by adding onion, finely diced potatoes, and green pepper; cook for a few minutes until lightly brown. The finely diced potatoes in my beef empanada recipe helps add to the flavor. Potatoes are like flavor sponges.
Then add garlic and remaining ingredient MINUS the sauce. Cook for 20 minutes with the lid partly open to help evaporate liquid and stir often.
Add sauce and cook for an additional 10 minutes. The sauce will help keep the meat from becoming dry, which is a common problem in many recipes. Always give it a few good stirs at the end and taste your beef filling. Adjust salt and pepper if needed.
Dab your fingers in water to moisten the edges of each empanada to ensure a good seal. Place about two tablespoons of meat filling in each circle and fold the dough to form the empanada.
You can use your fingers to pinch little pleats; however, to follow tradition I use a fork for crimping. Lastly, use your fork to create vents on the top. This will help avoid the empanada from cooking unevenly while frying or baking.