Quince quarter, peel and remove core. Cut into small cubes and simmer in approx. 200 ml of water and a little lemon juice for approx. 15 minutes (should be so soft that you can use the hand blender to make puree.)
Beat the butter, sugar and eggs until very frothy. Mix flour with baking powder and stir in. Then stir in the cooled quince puree (should be 150g). Add the chocolate chips as well.
Spread on a greased baking sheet and bake for about 25-30 minutes at 175 degrees U / O heat. Chopstick test is useful. Dust with powdered sugar