Best Cookie Butter Brown Sugar Slab Pie Recipe

Ingredients

• 2 ½ prepared single pie crusts (storebought or homemade)
• ½ cup cookie butter spread (like Biscoff), plus more for decorating
• ½ cup dark brown sugar
• 1 Tbsp all-purpose flour
• 2 tsp cinnamon, divided
• ½ tsp fine sea salt
• 1 egg
• 1 ½ cups powdered sugar
• 1-2 Tbsp milk
• ½ tsp vanilla extract