In a large saucepan, combine about 1/4 cup of the cream, the brown sugar, cinnamon, salt, and eggs. Whisk until very smooth. Add the rest of the cream and the 1/3 cup of biscoff cookie butter spread.

Cook and stir the mixture over medium-low heat for 8-10 minutes, or until the temperature reaches 165°. It should thicken enough to coat the back of a spoon.

Strain the ice cream mixture through a fine-meshed wire strainer. Stir in the vanilla extract and milk.

Cover and chill for 8 hours or overnight.

Pour the chilled mixture into the canister of an ice cream maker. Churn according to the manufacturer's instructions.

In a freezer safe container, layer a third of the ice cream, a third of the biscoff cookie pieces, and a third of the biscoff spread. Repeat two times.

Cover and place in the freezer. Freeze for 3-4 hours, or until firm enough to scoop.