Set oven rack in the middle and preheat oven to 325° F.
In the bowl of the stand mixer, cream together the butter and the cream cheese. Add the sugar a little at a time, mixing on medium speed until light and fluffy.
Add the eggs, one at a time, mixing on low just until the yolk is no longer visible.
In the medium bowl, sift together the flour and the salt. Add the flour and salt to the butter mixture a little at a time, alternating with the bourbon, mixing on low each time just until blended. Be gentle. Don't over mix, or the cake will be tough and lose volume. Start with the flour and end with the flour. (You can also do this part by hand using a spatula to fold in the flour and bourbon.)
Gently fold in the vanilla extract and the pecans.
Pour into the prepared tube/Bundt pan and bake for 1 hour 30 minutes to 1 hour 45 minutes, using a long bamboo skewer to check cake consistency. Skewer should come out dry, but may have a few crumbs clinging. Remove from oven and cool in the pan on a wire rack for 15 minutes. Remove from pan and cool completely on the wire rack.
In the bowl of the stand mixer, cream together the butter, cream cheese, and vanilla. Add the sifted sugar a little at a time until the sugar is fully mixed in. Add milk a little at a time, mixing as you go, until the glaze drizzles easily from a spoon. Depending on humidity, you may need a little more or a little less milk.
Drizzle the glaze around the top of the cake, allowing it to run down the sides. Sprinkle the colored sugars on top of the glaze.