For the Guinness Chocolate Bundt Cake:

1. Preheat oven to 325°F (163°C).

2. In a large bowl, whisk together granulated sugar, brown sugar, flour, cocoa powder, espresso powder, baking soda, baking powder, and salt. Break up any large clumps.

3. In another bowl, whisk eggs, sour cream, Guinness, milk, oil, and vanilla until fully combined.

4. Pour wet ingredients into dry ingredients and mix until just combined—do not overmix.

5. Grease a 10-cup Bundt cake pan thoroughly with nonstick spray and pour in the batter.

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

7. Let the cake cool for 15 minutes in the pan, then invert onto a cooling rack. Once fully cooled, flip right side up to frost.

For the Baileys Buttercream:

1. In a stand mixer fitted with a paddle attachment (or using a hand mixer), beat butter on medium speed until smooth.

2. Reduce speed to low and gradually mix in confectioners’ sugar.

3. Add Baileys, milk, vanilla, and salt, and beat until smooth.

4. Mix in melted white chocolate, then increase speed to medium-high and beat until fluffy.

5. Spread over the cooled cake.

For the Irish Whiskey Salted Caramel (Optional):

1. In a medium saucepan, whisk together sugar and water over medium-low heat until fully dissolved (about 5 minutes).

2. Add butter and bring to a slow boil over medium heat. Cook until the mixture turns a deep golden brown (10-12 minutes). Do not stir during this time!

3. Remove from heat and carefully whisk in heavy cream and whiskey (the caramel will bubble aggressively).

4. Stir in vanilla and salt, whisking until smooth. Let cool for 20 minutes, stirring occasionally.

5. Drizzle over the frosted cake and enjoy!