Line the dish of your choice with foil. Using 1 tbsp of butter, coat the foil.
In a large sauce pan, mix remaining butter, sweetened condensed milk and white chocolate over a low heat until melted and mixed well.
Remove from heat and mix in pecans and kahlua
Spread into foiled dish and chill over night or for no less than 2 hours.
Remove foil and cut into 1 inch squares. Seperate with parchment paper to avoid sticking and store in refrigerator.