Dough:

Cup of Yum
1. Preheat the oven to 160 degrees Celsius/ 320 degrees Fahrenheit. Grease a baking dish, about 32x22 cm/ 12x9 inches.
2. Divide 3 of the eggs. Set the egg whites aside for the filling of the cake.
3. Place the lard/shortening, the 3 egg yolks, the remaining whole egg and 150 g/ ¾ cup sugar in a bowl and mix until pale and fluffy.
4. Mix the flour and the baking powder together and add them to the egg mixture. Mix until incorporated but don't overdo it. Take about one-third of the dough, wrap it in cling film and place in the freezer until you prepare the rest.
5. Break the remaining dough into several pieces, flatten them a bit, and place them into the prepared baking dish. Press them with your hands and fingers until you get an even layer that covers the bottom of the baking dish entirely.

Filling:

1. Clean the beaters of the mixer very thoroughly before beating the egg whites. Beat the egg whites with a pinch of salt until stiff. Slowly add the remaining 150 g/ 5.3 oz/ ¾ cups sugar and continue beating until the mixture is stiff and glossy.
2. Fold in the ground walnuts and the stirred jam. Spread this mixture over the dough layer in the baking dish and level.

Crumbles:

1. Take the remaining dough out of the freezer and grate it evenly over the cake. Use the coarse shredder on your box grater.
2. Bake the cake in the preheated oven for about 35-40 minutes or until golden brown. Let cool and cut into squares.
3. It keeps well for several days in an airtight container.