Mix everything in a bowl and knead. You can use a stand mixer with a hook attachment, hand mixer with a swirl attachment or by hand.
Stop kneading when you can perform a window test successfully: grab a ball of dough and start stretching it slowly until you can see through the center. If it breaks then it needs more kneading.
Let proof covered with a cloth until it doubles in size. If your kitchen is cold, put it inside a turned off warm oven. Mine took 20min.
Knock out the air and roll it into a rectangle where the shortest side is the same length as the longer side of the mould.
Butter and flour the mould for easy unmoulding later.
Brush the dough with butter and then sprinkle the cinnamon sugar and walnuts over it.
Roll it and then tuck the ends underneath the roll to make it fit the mould.
Let proof until it doubles in size once again.
Break the eggs and mix with the water. Brush it on the proofed bread.
Take the bread to a pre-heated oven at 180C until it's nice and golden: 30-35min.