In a large mixing bowl, cream together 1 cup of softened butter and 1 cup of granulated sugar until light and fluffy, about 3 minutes.

Add 2 eggs and 1 teaspoon of vanilla extract, mixing until fully combined.

Gradually incorporate 3 cups of flour, 1 teaspoon of baking powder, and a pinch of salt, stirring until a soft dough forms.

Divide dough into two equal disks, wrap each in plastic wrap, and refrigerate for about 1 hour until firm.

In another bowl, blend 1/4 cup of softened butter, 1/2 cup brown sugar, 1/4 cup granulated sugar, and 2 tablespoons ground cinnamon to form a smooth paste.

Roll out one chilled disk of dough into a rectangle about 1/4 inch thick, brush with melted butter, and spread the cinnamon filling evenly, leaving a 1-inch border.

Roll tightly into a log, seal with water, wrap in plastic, and chill for another 30 minutes.

Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper. Slice the log into 1/2-inch rounds.

Arrange on baking sheet and bake for 12-15 minutes until edges are lightly golden.

Whisk together 1 cup powdered sugar, 2 tablespoons milk, and 1/2 teaspoon vanilla extract for icing. Drizzle over cooled cookies.