Add your hot coffee to a large mug along with the erythritol (if using). Add the coconut oil and butter. Stir well to combine, melting the butter and oil into the coffee and dissolving the sweetener.
Step 2
Taste the coffee and adjust the sweetener if needed. Carefully use a handheld stick blender or milk frother and blend the coffee, combining the fats with the hot coffee. The coffee should be smooth and creamy with a layer of foam on top, then serve immediately.