Activate Yeast: Warm the milk(110 deg), add 1 tablespoon of the sugar, sprinkle in the yeast, stir, and let sit 5–7 minutes until bloomed.
Mix Dry Ingredients: Whisk together the flour and salt; set aside.
Combine Dough Ingredients: Add the activated yeast mixture to a stand mixer bowl, then add the remaining sugar, sour cream, butter, eggs, vanilla, and the flour mixture.
Initial Mix: Mix on low for 1 minute with dough hook until just combined. Let the dough rest for 5 minutes to settle before you continue mixing
Scrape sides down and mix on medium speed for 5–7 minutes until smooth, elastic, and pulling from the bowl’s sides. Add small amounts of flour only if needed; dough should remain slightly sticky.
Transfer dough to a greased bowl, cover in semi warm environment, and let rise 30–45 minutes.
During this time, make your filling: Combine softened butter, brown sugar, cinnamon, and vanilla;
Grease a 9×13 inch baking pan that you will use to bake.
Roll Out Dough: Turn risen dough onto a floured surface, dust the top with flour, and roll into a large rectangle. It doesn't need to be super thin.
Spread the cinnamon filling evenly across the dough, leaving a small border.
Drizzle about 4-6 tablespoon of your melted biscoff on top of your filling
Add in half of your crushed Biscoff cookies on top of your filling before rolling
Shape Rolls: Roll up tightly from the long side. Slice into 8-10 large rolls using a sharp knife or floss.
Arrange in Pan: Place rolls in your baking dish. they can sit close to the edges with space in the middle so they have room to expand.
Cover and let proof for another 25–30 minutes in semi warm environment.
Preheat Oven: Heat oven to 350°F.
Warm heavy cream for 15 seconds in microwave and pour over the proofed rolls.
Bake at 350°F for 22–24 minutes, then increase to 375°F for 5–7 minutes.
Make Frosting while rolls are baking: Beat the cream cheese and butter until fluffy, then mix in powdered sugar and vanilla until smooth.
Add 3-4 tablespoon of your melted biscoff into your frosting and mix
Let baked rolls rest 10–15 minutes when done and then spread frosting over the warm rolls.
Drizzle 3-4 tablespoon of melted biscoff on top of your frosted cinnamon rolls
Top with the remaining ½ of your crushed biscoff cookies