1. Mix the heavy cream with olive oil and ground coffee. Place in an airtight container and refrigerate overnight.
2. Strain the coffee mixture well, and discard the ground coffee. Transfer the strained liquid to a blender or a food processor.
3. Add the sugar and salt, and process until the fat forms into butter and the liquid separates.
- 4. Transfer the mixture to a large piece of cheesecloth and wring out any excess liquid.
5. Transfer the butter to a serving bowl, garnish with flaked salt and serve immediately or store in the refrigerator.