Sift the flours and the salt together into a large bowl. Mix in the sugar and then make a well in the center.
In a bowl, add the milk, egg, oil, and water, and whisk to combine. Pour the liquid ingredients into the well in the dry ingredients. Gradually mix the flour into the wet ingredients with a fork or butter knife. Gather the dough together with your hands and knead for about 8 minutes to form a soft dough.
Cover the dough with a clean, damp cloth and rest for 30 minutes.
Knead the dough for an additional 2 minutes then divide the dough into 10 equal portions that are about 70 grams each. Roll each one into a ball. Cover with the towel.
Heat your pan over medium-high heat. While the pan heats, roll each ball out as thinly as you can.
Place the chapati in the pan and cook for 1 to 2 minutes on each side. Use a damp towel that is folded several times to press down on the chapati while it cooks. Keep it moving around the pan.
Repeat the rolling and cooking with each ball of dough. Serve Warm. Store leftovers airtight for up to 2 days. Reheat in a hot pan before serving.