Melt the butter in a medium saucepan on high, stirring occasionally.
While browning the butter, place dehydrated milk packets on a medium sized sheet pan and put in the oven at 450F. Check and mix every few minutes, ensuring the top layer does not burn. Repeat 3-4 times until toasted throughout, 10-12 minutes.
Boil the butter and mix continually. When the butter is fully melted, do not stop stirring (leaving the butter for just a few seconds without stirring could burn it.) When the butter is completely melted and starts to foam, it is nearly finished. Mixture is ready when it turns a dark brown and the butter has brown solids throughout.
Combine the toasted milk solids and brown butter mixture. Stir. Add the bourbon.
Put in a large container covered, and refrigerate for 48 hours. After 48 hours, strain through cheesecloth.