Warm the milk (not too hot to where you can’t touch it), then stir in the sugar and yeast. let it sit for 5–10 minutes until foamy.
Add in the egg, egg yolk, melted butter, and salt, then begin adding the flour. mix until a dough forms.
Knead lightly, adding a little more flour as needed until the dough is no longer sticking to your hands but still tacky.
Knead using a bit of oil instead of flour until smooth.
Place the dough into an oiled bowl, cover with plastic wrap and a towel, and let rise in a warm spot for about 1 hour or until doubled.
For the filling, add the biscoff cookie butter to the hot melted butter and let it melt slightly.
Stir in the brown sugar and cinnamon until combined.
Roll out the dough into a rectangle, spread the filling evenly over the surface, then sprinkle the crushed biscoff cookies on top.
Roll the dough up tightly and cut into rolls.
Place into a greased baking dish and let rest for about 15–20 minutes.
Bake at 350°F until golden and cooked through, about 20–25 minutes depending on size.
For the frosting, whip the softened cream cheese and biscoff cookie butter together until smooth.
Add the softened butter and mix again, then add the powdered sugar and vanilla and whip until fluffy.
Spread over warm (not hot) rolls and finish with extra crushed biscoff cookies on top.
