Whisk flour, salt and baking powder together in a medium bowl. Add softened butter or oil and use a fork to combine until crumbly mixture forms.
Stir in warm water and mix with until a shaggy dough forms. Use your hands to gently knead the dough in the bowl to get the mixture to form a rough ball.
Turn dough onto a floured surface and knead for another 1 to 2 minutes or until smooth and not sticking to the surface.
Cut the dough into 10 pieces for taco-sized tortillas or 4 pieces for large burrito-sized tortillas. Shape each portion into a ball using your hands and tension of the work surface.
Cover the dough balls with a light kitchen towel to rest. Let the dough rest for 20 minutes up to two hours. If you are making the dough in advance, you can store the tortillas balls in an airtight container in the fridge for up to 24 hours.
Using a heavy rolling pin, roll out each ball until very thin (until you start to see the work surface through them.) For taco-sized, the balls should roll out to about 6 to 8 inches. For burrito-sized, about 10 to 12 inches.
Heat a large cast iron skillet to medium-high heat. Do not add any oil to the pan. Wait until pan is HOT to start cooking the tortillas. Lay the rolled out tortilla in the pan and cook on first side until it puffs slightly (around 30 seconds). You will hopefully see little brown spots on the underside appear, this means time to flip! Flip with spatula and cook again till lightly brown. If the skillet is hot enough, cooking time should be about 60 seconds to 1 minute total.
Stack tortillas on a plate or in a tortilla holder and cover with a light kitchen towel while you continue making the rest of the tortillas.