Begin by combining the flour, baking powder, salt, and shortening in a bowl, ensuring they are well mixed. Next, add the milk, bringing everything together to knead a soft dough. Cover the dough and set it aside for 15 to 20 minutes.
After allowing the dough to rest, gently divide it into 14 pieces of equal size. Pick up one of the dough balls and use a rolling pin to flatten it into a circle with a diameter of approximately 5 inches. Next, use a fork to prick the rolled-out dough a few times. ( pricking will help to keep chalupa flat)
To begin, heat oil in a pan over medium heat until it reaches the proper temperature for frying. Carefully transfer the dough into the hot oil. You should observe that the dough will float and expand immediately. Allow the dough to fry for approximately 30 seconds on one side before flipping it over.
Remove the chalupa shell and let it drain on a paper towel. Repeat with all the shells.
Place red salsa in a blender, and purée until very smooth, at least minute, or leave salsa chunky, if you prefer. Transfer to a bowl, clean out blender, and repeat with salsa verde.; transfer salsa verde to a separate bowl. Using a spoon, place about 2 tbsps. salsa roja on top of half the tortillas, spreading it to the edges; repeat with salsa verde and remaining tortillas.
Add shredded chicken, cheese(optional), diced onions and place in oven 400°F, for 6-8 minutes. Remove, and serve with rice or beans, Enjoy!