Weigh the butter in advance and leave it at room temperature until it softens.
Heat the water until lukewarm and pour it into a bowl.
Add yeast to the water and stir until dissolved.
Then add sugar and salt to the bowl and mix together.
Gradually mix in some wheat flour. Use your hands when necessary. Continue until the dough is firm but pliable.
Knead the butter into the dough with your hands.
Place the dough back in the bowl and let it rise for 45 minutes.
Find a grater and grate the squash, so it’s ready when the dough has risen.
When the dough has risen, sprinkle some flour on the table.
Turn the dough out onto the table.
Make a depression in the middle of the dough and crack the egg into it.
On top of the egg, place the grated squash and ham strips, then fold the dough over.
Divide the dough into 9 - 10 pieces with a knife or dough scraper.
Place baking paper on a tray and arrange the ham rolls on the tray.
Let them rise on the tray for half an hour.
Bake them for about 20 minutes at 200 degrees Celsius (392 degrees Fahrenheit) in a conventional oven. They are done when they are golden, so they may need less time in your oven.