Taco Bell Double Decker Taco

1 1/2 tablespoons masa harina
4 1/2 teaspoons chili powder
1/2 teaspoon onion powder
1/2 teaspoon garlic powder
1/2 teaspoon seasoning salt
1/2 teaspoon paprika
1/4 teaspoon ground cumin
1/2 teaspoon garlic salt
1/4 teaspoon sugar
1 teaspoon dried minced onion
1/2 teaspoon beef bouillon powder
1 1/3 pounds ground chuck
Shells and Toppings
1 can refried beans
12 soft flour tortillas
12 crispy taco shells
1/2 head iceberg lettuce shredded
1 cup shredded cheddar cheese
2 Roma tomatoes diced
1 cup sour cream optional

Combine all the ingredients for the beef filling in a small bowl, except for the ground chuck. Mix well.
Crumble the ground chuck into a large skillet (preferably nonstick) over medium-high heat and cook, stirring, until the meat has browned. Drain the beef in a strainer over the sink and rinse with hot water.
Return the beef to the pan along with the spice mix and 3/4 to 1 cup of water. Stir to combine and simmer on medium-low heat for 20 minutes, until most of the moisture has cooked away. Remove from heat before the pan is completely dry.
Heat the refried beans in a small pot on the stove over low heat for about 5 to 8 minutes or until the beans have warmed through and are soft.
Wrap the soft flour tortillas in a clean towel and sprinkle the towel with a few drops of water. Microwave on high power for 30 to 45 seconds or until the tortillas are soft and pliable.
If desired, warm the crispy taco shells in the oven at 350°F for 7 to 10 minutes.
To assemble to tacos, spread about 1 tablespoon of refried beans on a soft tortilla and fold the bean-covered soft tortilla around the crispy taco shell. Spoon a few tablespoons of meat into each taco shell. Top with lettuce, cheese, tomatoes, and sour cream, if desired. Repeat with the remaining shells and fillings and serve immediately.