I enjoy keto coffee too. I replace the coconut oil with MCT oil, did not like the coconut taste.
My recipe...
Fill blender with hot water
Make a cup of coffee (I use a Starbuck's Pike Place k-cup brewed on medium)
Dump out the water from the blender
Add 1 tbsp MCT oil, 1 tbsp butter (unsalted kerrygold is really good in this but I usually just have salted land o lakes...), 1 tsp heavy whipping cream and the coffee to the blender.
Blend 30 seconds and enjoy
having an actual blender makes this much better than a blender jar. However many blenders are not rated for hot liquids so be careful.