In the bowl of a stand mixer, combine the warm milk, active dry yeast, and 1 tbsp (15g) of the granulated sugar. Whisk gently to combine. Let the mixture sit for 5-10 minutes. You are looking for a frothy, bubbly surface.

Add the remaining sugar, melted butter, whole egg, egg yolk, and kosher salt to the yeast mixture. Whisk until smooth. Attach the dough hook. Gradually add the bread flour on low speed until a shaggy dough forms. Increase the speed to medium and knead for 5-7 minutes until soft and slightly tacky.

Form the dough into a smooth ball and place it in a lightly oiled bowl. Cover with a warm, damp towel and let it rise in a draft-free spot for 1 hour, or until doubled in size.

Punch down the dough and transfer it to a lightly floured surface. Roll the dough out into a 12x18-inch (30x45cm) rectangle. Spread the softened butter evenly across the dough, then spread the warmed Biscoff cookie butter over the butter layer. Evenly sprinkle the brown sugar and ground cinnamon over top.

Starting from the long end, tightly roll the dough into a log. Using unflavored dental floss or a serrated knife, cut the log into 12 equal slices. Place them cut-side up in a greased 9x13-inch (23x33cm) baking dish.

Cover the baking dish tightly with plastic wrap or a warm towel. Let the rolls rise for 30-45 minutes until noticeably puffy and touching each other. Preheat oven to 350°F (175°C).

Bake the rolls on the center rack for 22-25 minutes until a light golden-brown crust forms on top. Remove from the oven and let them cool for 10 minutes.

In a medium bowl, beat the softened cream cheese and Biscoff cookie butter until completely smooth. Add the sifted powdered sugar and heavy cream. Beat on high speed until you achieve a thick, glossy, light brown glaze.

While the rolls are still warm, generously swirl the glaze over the top so it drips down the sides. Immediately sprinkle with finely crushed, golden-brown Biscoff cookie crumbs. Serve warm.