2 cups all-purpose flour
1-1/2 teaspoons baking powder
1 teaspoon salt
2 teaspoons vegetable oil
3/4 cup lukewarm milk or water (2% is fine)

Stir together the flour and baking powder in a large mixing bowl. Add the salt and vegetable oil to the lukewarm milk and whisk briefly to incorporate. Gradually add the milk to the flour, and work the mixture into a dough. It will be sticky.
Turn the dough out onto a surface dusted with flour and knead vigorously for about 2 minutes (fold and press, fold and press). The kneading will take care of the stickiness. Return the dough to the bowl, cover it with a damp cloth, and let it rest for 15 minutes. (This dough will not rise, but it needs a rest.)
Divide your dough into 8 balls of equal size, cover them, and let them rest again for about 20 minutes. Avoid letting them touch, if you don’t want them to stick together.
Dust your work surface with flour. Working one at a time, remove each piece of dough and pat it into a 5-inch circle. With a rolling pin, roll out the tortilla, working from the center out, until you have a 7- or 8-inch tortilla a little less than 1/4 inch thick. You may need to dust the rolling pin with flour. Transfer the tortilla to a hot, dry skillet or griddle. It will begin to blister. Let it cook for 30 seconds, turn it, and let the other side cook for 30 seconds. Remove the tortilla, place it in a napkin-lined basket and cover with aluminum foil. Repeat for the remaining tortillas.
Although flour tortillas, like corn tortillas, are best if eaten right after they are made, these tortillas will freeze well. Wrap them tightly in plastic, and they will keep, frozen, for several weeks. To serve tortillas that have been frozen, let them thaw and come to room temperature, then wrap them in aluminum foil and heat them in a warm oven. Microwaving tends to toughen them.
Once you get a rhythm going, you can roll out a tortilla, put it on to cook and, while it cooks, roll out your next tortilla. Be sure to rewrap your fresh tortillas each time you add another to the stack.
You can substitute one cup of whole wheat flour for one cup of the all-purpose flour.