Step 1

Preheat oven to 180C. Line a 9×13 inch baking pan with parchment paper and set aside.

Step 2

Melt butter and chocolate in a small heat proof bowl over simmering water. Let it reach room temperature.

Step 3

Mix eggs and sugar with an electric mixer. until creamy.

Step 4

Add in finely grated apples and mix.

Step 5

Pour in melted chocolate and butter. Keep mixing.

Step 6

Add cocoa powder and mix with a spatula.

Step 7

Mix flour, vanilla and baking powder in a separate bowl. Slowly add them sifting into the batter.

Step 8

Pour the batter into the prepared pan.

Step 9

Toss ground walnuts on it and bake fore 35 minutes.

Step 10

Let it cool down before cutting into squares.