Add Fire Up the Grill loose tea directly to the milk. Place into the refrigerator to cold-steep overnight (10-12 hours). Then strain the milk and set aside.
In a large sauce pan, melt butter in olive oil. Once melted, stir in flour. Heat and stir for a minute or two, making sure all flour is incorporated. Add the milk, whisking until thick and bubbly. Remove pan from heat and slowly whisk in the cheese. (You do not want to boil the cheese, it will separate and curdle.) When melted, stir in cooked pasta.
Campfire Mac & Cheese from https://www.adventureswithtea.com/campfire-mac-n-cheese/