Line a loaf pan with parchment paper.

In a medium mixing bowl, stir together the vanilla extract, sweetened condensed milk and ⅓ cup of Biscoff cookie butter until combined.

In a large mixing bowl, use a hand mixer with whisk attachment to whip the heavy cream to medium stiff peaks. Alternatively, whip the cream with a whisk attachment in a stand mixer to medium stiff peaks.

Melt ⅔ cup of the Biscoff cookie butter on low in the microwave in 10-20 second intervals until melted / more of a liquid texture and then set aside.

Pour the sweetened condensed milk mixture into the whipped cream mixture and gently fold everything together to combine (it should be fairly smooth). Be careful not to overmix.

Pour half of the whipped cream mixture into the prepared loaf pan and drizzle with 1/3 cup of melted Biscoff cookie butter and then crumble over 6 Biscoff cookies. Use a knife to swirl it into the ice cream mixture. Pour in the remaining whipped cream mixture and top with the rest of the melted Biscoff cookie butter and 6 more crumbled Biscoff cookies. Use a knife to swirl it into the mixture again.

Cover tightly with plastic wrap and freezer for at least 8 hours or overnight before serving. If the ice cream is too difficult to scoop, let it warm up for about 5 minutes on the counter.

Store in the freezer, covered well with plastic wrap, for up to one month.