Preheat your oven to 350°F (175°C). Grease and flour a bundt pan.

In a bowl, whisk together flour, baking powder, and salt. Set aside.

In a large mixing bowl, cream the butter and sugar until light and fluffy.

Add the eggs one at a time, beating well after each addition. Stir in vanilla extract.

Gradually mix in the dry ingredients, alternating with the Irish whiskey and milk, beginning and ending with the dry ingredients.

Fold in chopped walnuts, if using.

Pour the batter into the prepared bundt pan and smooth the top.

Bake for 50-55 minutes, or until a toothpick inserted in the center comes out clean.

While the cake bakes, prepare the glaze by melting the butter in a saucepan over low heat. Stir in powdered sugar and whiskey until smooth.

Once the cake is baked, allow it to cool slightly, then drizzle the whiskey glaze over the warm cake. Let it cool completely before serving.