1. Preheat the oven to 180°C (350°F).
2. In a large bowl, mix together the peanut butter, vegetable margarine, and sugar.
3. Add the egg and mix, then add the cornstarch, rice flour, and baking powder.
4. Mix thoroughly to obtain a homogeneous dough, then incorporate the chocolate chips.
5. Form small balls of dough and place them on a baking sheet lined with parchment paper.
6. Using a fork, lightly flatten the small balls of dough.
7. Bake for 15 minutes, until the cookies have a slightly golden color.
8. Allow to cool before enjoying.