Did some skimming earlier:
coffee + butter + mct/coconut oil, can even replace the butter with ghee
Butter/fat helps absorb caffine slower -> less jitters, less crash, caffine effect lasts longer
mct (oil):
"Usually, people use MCT for help with:
Problems taking in fat or nutrients
Weight loss
Appetite control
Extra energy for exercise
Inflammation"
https://www.webmd.com/diet/mct-oil-health-benefits-common-uses
Supposedly mct also helps your body/brain absorb ketones, but not too sure about that.