In a large bowl*, combine the flour, baking powder, and salt. Stir to combine. Add the sourdough discard, hot water, and melted butter (or oil). Mix with a wooden spoon or by hand until the dough starts to come together. Transfer to a smooth work surface and knead for 1-2 minutes until the dough is smooth.
Divide the dough into 12-16 pieces (16 pieces for smaller street tacos, 12 pieces for larger burritos). Shape each piece into a ball in the palm of your hand, then flatten slightly. Cover with a clean kitchen towel or piece of plastic wrap and let rest for 30 minutes.
Working with one piece at a time (and keeping the others covered), use a rolling pin to roll each piece into a roughly 8-inch round. You want these to be very thin!If you have someone cooking with you, it may be easiest to have one person rolling and one person cooking the tortillas.
Heat a large skillet over medium-high heat (a cast iron skillet is great for this). Cook the tortillas for 30-45 seconds on each side, until the dough is bubbly and golden brown spots appear on the bottom.
Wrap the cooked tortillas in a clean kitchen towel to keep them warm and soft. Serve while warm, or let them cool fully for storage.
Notes
Nutrition information is based on 16 tortillas (1 per serving). *You can also make these tortillas in a stand mixer. Mix the ingredients together until a rough dough forms, then knead by hand for 1-2 minutes to make a smooth dough. To make this recipe with active sourdough starter, replace the sourdough discard with active starter (200g). All other ingredients will remain the same.