Mix flour and salt together. Mix butter and water, then stir into dry ingredients until just mixed. Scoop it up in hands and shape into a ball. Knead it for 2 or 3 minutes. Cover with a damp cloth and let it rest for 30 minutes - very important, as letting it rest will make it easier to roll out. Divide dough into 8 pieces. Flatten a little with your hand, then roll each piece out on a lightly floured board, flipping over every few strokes. Cook in an ungreased, hot frying pan on each side. Mine turned out the best when I used medium/high heat. Tip: lift up edge of tortilla, and if the underside is bubbly and lightly browned, it is ready to turn.
Conversion for other flours:
Whole wheat 2 cups ( I haven't tried this one)
Kamut 2 cups - very good
Millet 1 cup millet and 1 cup whole wheat (I haven't tried this one)