Preheat oven to 325°F (170°C).

For cake: In the bowl of a stand mixer fitted with the paddle attachment, beat butter, brown sugar, and granulated sugar at medium speed until fluffy, 5 to 7 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating well after each addition; scrape sides of bowl. Beat in vanilla.

In a medium bowl, whisk together flour and salt. In a small bowl, combine liqueur and buttermilk. With mixer on low speed, add flour mixture to butter mixture in three additions alternately with liqueur mixture, beginning and ending with flour mixture, beating just until combined after each addition.

Spray a 10-cup Bundt pan with baking spray with flour. Spoon batter into prepared pan, smoothing top with an offset spatula. Firmly tap pan on a kitchen towel-lined counter several times to settle batter.

Bake until a wooden pick inserted near center comes out clean, 1 hour and 10 minutes to 1 hour and 20 minutes, covering with foil halfway through baking to prevent excess browning. Let cool in pan for 15 minutes. Invert cake onto a wire rack, and let cool completely.

For glaze: In another medium bowl, whisk together confectioners’ sugar, melted butter, liqueur, and vanilla until smooth and well combined; spoon onto cooled cake. Store in an airtight container for up to 3 days.