Cream margarine with brown sugar and white sugar. Add egg and vanilla. Mix well. Stir in peanut butter, bicarb soda and salt. Make sure it is well blended. Add flour and chocolate chips.
Drop teaspoons of cookie dough then flatten with fork slightly on greased baking tray. Bake for 5-6 minutes or until just showing a hint of brown on edges. Don't overcook. Let cool on baking tray for 5 -10 minutes. Then transfer to cooling rack.
If using parve chocolate chips, your biscuits will be parve. If using milk chocolate chips, your biscuits will be dairy.