Preheat the oven to 180 degrees C. Grease baking tray or line with baking paper.
In a large bowl, beat sugar and butter until light and fluffy. Mix in the eggs one at a time. Sift together the matzo cake meal, salt and potato starch. Stir into the batter just until blended. Gently mix in the walnuts and chocolate chips. Chill the dough briefly so it will be easy to handle.
Divide the dough into halves and form each half into a 12cm wide loaf that is about 2cm thick. Sprinkle cinnamon sugar over the top.
Bake for 45 minutes in the preheated oven. Cool then slice into 2cm slices to serve.
Matzo cake meal
If you can't find matzo cake meal, you can grind matzo meal in your food processor until it becomes finer.