Start by peeling the potatoes, put them to boil until semi-cooked. Be careful not to over-boil them because you'll be grating them and it's not desirable to mash them.
Meanwhile, mix the mince with 1 of the eggs, add the finely chopped onions as well. Season with salt and black pepper. While the potatoes are still boiling, prepare the carrots - peel them and cut them into long sticks (optionally put them in boiling water for a minute to soften slightly). Tear the washed parsley as well - you need about a handful with the leaves.
Once the potatoes are boiled, cool them under running water. Grate them coarsely and add the other 2 eggs, plus salt to taste. Add the flour and knead into a dough-like mixture (it needs to be relatively dense so it doesn't fall apart when you're making the roll and baking). You can add a little more flour or breadcrumbs - depending on how much it absorbs and how the potato mixture forms.
Next, it's time to form the roll itself. Pour the breadcrumbs onto baking paper (to help you form it). You can use coarse or fine breadcrumbs (or ones with added herbs and spices), the former makes for an appetizingly crunchy crust.
Next roll out the potato "dough" - the goal is to obtain a rectangle and distribute the mixture evenly. Put the mince on top, distribute it all over the entire rectangle. Arrange the carrots lengthwise in the direction you'll be rolling up the roll in. Put the parsley on top.
Using the baking paper it's on, roll it up into a roll (the tighter the better) and put it in an oven dish laid out with baking paper. Cover it with aluminum foil and bake in a preheated 356°F (180 °C) oven for 30 min.
Remove the foil and bake about another 15 min. until ready. You can serve the cut up pieces of roll with fresh salad, dairy sauce or simply decorate with parsley and chopped vegetables (tomatoes, cucumbers and others).