Whisk the flour, salt, and baking powder together in a medium bowl.
Add the butter (or lard) and mix in well using your hands. The flour will become more crumbly with small pieces of butter no larger than a pea. No large pieces of butter should remain. The flour will become a very pale yellow.
Add the water, a bit at a time, stirring the flour into the water using a fork, until the dough becomes raggedy. Spill it out onto a work surface, and knead into a ball. Add additional water as needed. The dough should be smooth, not sticky, but not dry. If it sticks to the countertop as you knead it, add a little additional flour. PRO-TIPS: Be careful not to add too much additional flour, as that can make the tortilla more tough. For the same reason, don't knead much longer than it takes to get a smooth ball of dough.
Clean out the bowl you were using, lightly oil, and place the ball of dough in it. Cover lightly with plastic or a towel. Let rest for 20 minutes.
PRO TIP: Always cover the dough when you're not working with it, as it will form a thin crust as it dries out.
Divide the dough in half. Squeeze and twist off 6 smallish balls. Cover, and repeat with the other half of the dough. Cover.
Either use your fingers to form tortillas that are between ⅛" and ¼" in thickness, or use a rolling pin. The tortillas expand a little when placed on the grill.
NOTE: If using a tortilla press, place a piece of wax paper on the bottom of the press. Set a ball of dough on top, and cover with another piece of wax paper. Close the press to flatten the ball. It will take a little practice to get the thickness you prefer. Repeat with the rest.
Heat up a griddle over medium heat. If it's non-stick, it's not necessary to oil it to cook the tortillas. If your griddle is not non-stick, use only a very thin slick of oil, as the dough will absorb it.
Cook for 2 minutes per side, turning once. Remove and stack in a tortilla warmer, or wrap in foil to keep warm.