1. Mix all the seasoning ingredients together.
2. Cut up the beef into strips and place in a bowl. Add the seasoning and mix to completely cover.
4. To make the tortillas: in a bowl, using a whisk, combine the flour, baking powder and salt. Add the shortening (and/or lard) and rub into the flour mixture until well incorporated.
5. Gradually mix in the water until the dough comes together. It should be a medium-stiff consistency, not a soft as bread dough but not firm either. Add additional water if needed a Tablespoon at a time.
6. Turn the dough out onto a floured surface and knead until smooth.
7. Divide the dough into 12 portions and roll each into a ball. Set the balls on a plate, cover with plastic wrap, and let rest for at least 30 minutes.
8. Flatten the ball of dough, flour it, and then roll forward and backward across it once. rotate a sixth of a turn and roll forward and back again; continue rolling and turning until you reach the desired circle size. Roll all of them before going to the next step. I've found that adding a little extra flour between them helps to stop them sticking together.
9. Heat 2 tablespoons of vegetable oil in a cast iron skillet. Add the beef and cook, stirring frequently.
10. When the beef has browned add the bell peppers and red onion and continue to cook until they are done. Don't forget to stir it!
11. While the beef is cooking, cook the tortillas. Heat an ungreased griddle or cast-iron skillet over medium to medium high heat.
12. Lay the tortillas on the hot skillet, there may be a little sizzle noise and you will see bubbling across the surface.
13. After 45 seconds or so, when there are light brown marks on the bottom, flip it over and cook for another 30 - 45 seconds until the other side is slightly browned. Be careful not to leave it too long or it will become crispy. Remove from the skillet and place on a dry cloth. Repeat the process with the remaining tortillas and stack them one on top of the other on the cloth.
14. Serve immediately and with all the additions you like, cheese, sour cream, salsa, whatever takes your fancy.