Festive Eggnog Snickerdoodle Sandwich Cookies

Ingredients

• 2 teaspoons vanilla extract
• 1 teaspoon ground nutmeg
• 1 teaspoon vanilla extract, for the filling
• 2 large eggs
• pinch of salt, for the filling
• 1/4 cup eggnog, for the filling
• 1/2 teaspoon baking soda
• 1 ounce cream cheese, softened
• 1/2 teaspoon salt
• 3 cups powdered sugar
• 3/4 cup unsalted butter, softened
• 2 teaspoons cream of tartar
• 1/2 cup brown sugar, packed
• 2/3 cup eggnog
• 1 cup granulated sugar
• 2 teaspoons ground cinnamon
• 1/2 cup unsalted butter, softened, for the filling
• 3 cups all-purpose flour