1 cup unsalted butter 3.5 oz unsweetened chocolate 3 tbs cocoa 1.5 cups plain flour 1/2 tsp baking powder 1 tsp salt 4 eggs 2 cups sugar 1 tsp vanilla 1 cup chocolate chips
Set oven to 180°C.
Melt butter with unsweetened chocolate, and set aside to cool. Sift together cocoa, flour, baking powder and salt. Beat eggs until creamy, than gradually add sugar, beating constantly. Add vanilla and cooled chocolate. Stir in dry ingredients until just combined - do not beat.
Spread batter in buttered 23 cm. by 33 cm. pan. Sprinkle chips over the surface.
Bake for 30-35 minutes, or until the centre no longer jiggles when shaken. Cool and cut into 32 pieces.