Prepare the strainer by setting a fine mesh strainer over a medium mixing bowl.

Mix the dry ingredients: Combine brown sugar, cornstarch, and salt in a medium saucepan and whisk until well blended.

Gradually add 1/3 cup of whole milk while whisking until completely smooth, creating the base for your pudding.

Combine all ingredients: Stir in the egg yolks and remaining milk, whisking thoroughly to evenly distribute egg yolks.

Cook the mixture over medium heat, whisking frequently until it thickens, about 4-5 minutes.

Finish the pudding by removing from heat and adding unsalted butter and bourbon, stirring until fully melted.

Strain the cooked mixture through the strainer into the prepared bowl to eliminate lumps.

Chill the pudding in the refrigerator for at least 2 hours until set.