In a bowl whisk together flour, cocoa powder, bicarb soda and baking powder.
In another bowl with an electric mixer cream butter, peanut butter and sugar until light and fluffy. Beat in eggs, 1 at a time, beating well after each addition. Beat in flour mixture and stir in chocolate chips.
Drop dough by level tablespoonfuls 5cm apart onto buttered baking trays. Bake biscuits in batches in the middle of oven for 20 minutes. Cool biscuits on racks. Biscuits keep in airtight containers for about 5 days.