1In a food processor add the flour, sugar, baking powder and salt. Pulse for 2-3 seconds.
2Add the butter and pulse until the mixture resembles breadcrumbs. Add the egg and eggnog and pulse until combined and the dough starts to come together in a ball.
3Drop tablespoons of cookie dough on cookie sheets and place them in the fridge for 15-20 minutes.
4Meanwhile heat the oven to 350.
5Bake the cookies for 13 minutes or until the edges get slightly brown.
6Leave to cool completely before sandwiching them.
7In a small bowl mix the nutella with the remaining eggnog and place a teaspoon on each cookie and sandwich them. There should be 15-16 cookie sandwiches.
8Keep the cookies in an airtight container. They freeze well.