In a stand mixer, mix together flour, salt, and sugar.
Add softened butter, water with yeast, and egg yolks. Mix well.
Knead the dough for 8-9 minutes, then knead by hand for a couple of minutes.
Place the dough in a bowl and let it rise for 1-1.5 hours.
Melt butter and mix with brown sugar and cinnamon to make the filling.
Roll out the dough, spread the filling, and roll it up.
Cut the rolled dough into 12 equal-sized pieces and place in a buttered baking dish.
Let the buns rise until touching, then bake in the oven for 25-30 minutes at 190 degrees Fahrenheit.
Make a simple glaze for the buns.