In a mixing bowl, using a wooden spoon, stir flour and soy milk until a sticky dough forms.
Gradually add the extra flour - I usually add up to 1/3 cup, adding one tablespoon at a time and stirring between each addition. When it becomes difficult to stir with a spoon, oil your hands and knead the dough. The dough is ready when it is still soft, elastic a bit sticky but easy to form into a ball.
Grease a mixing bowl, place the dough ball in the center, cover it with a towel and let it rest for 20 minutes at room temperature. This step is optional, but it makes the flatbread fluffier.
Place the dough on a floured surface and divide it into 4 dough balls for larger flatbreads or 6 balls for smaller 5-inch flatbreads.
Flatten each dough ball with the palm of your hands, then use a rolling pin to roll the dough as thin as you like. The thinner, the less flexible and soft the flatbread will be.
Warm a cast-iron skillet, or non-stick pan over medium-high heat. Use a paper towel to rub olive oil all over the surface and prevent flatbreads from sticking to it.
Place the rolled flatbread in the hot pan, cover with a lid and cook for 1-2 minutes or until the surface shows bubbles and the bottom of the bread turns golden brown.
Flip on the other side and keep cooking for an extra 1-2 minutes or until cooked through.
Cool on a wire rack while cooking the remaining flatbreads.
Store the flatbreads wrapped in a kitchen towel to keep them moist. They can last 24 hours at room temperature, 3 days in the fridge, or 3 months in an airtight container in the freezer.
Note 1: To make your own self-rising flour, combine 2 cups of all-purpose flour with 3 teaspoons of baking powder.Note 2 (Soy milk swaps): any high-protein milk makes fluffy 2-ingredient flatbreads. Oat milk or protein-fortified almond milk are great swaps. Otherwise, use coconut yogurt. Low-protein milk like regular unsweetened almond milk makes the flatbread crispier.