Mix well wheat flour, salt and baking powder. Add lukewarm water a little by a little, while mixing them using your hand. Mix continuously until they are no longer sticky on your hands. Divide the dough into 4 parts. Roll each part of the dough using rolling pin until as thin as 1 millimeter. Low heat a skillet. Grill tortilla until crisp. Remove. Medium-low heat oil. Sauté chicken shreds and champignon along with oyster sauce for 2 minutes. Remove. Put a table spoon chicken mushroom sauté on each tortilla. Add mayonnaise, tomato ketchup and chili sauce, also cheddar cheese slices. Fold tortilla. Serve.