In a bowl, mash together the cream cheese and butter or ghee, or process in a food processor until smooth.
Preheat the oven to 325°F (160°C, or gas mark 3).
Line a rimmed baking sheet with parchment paper. Be sure to use a rimmed sheet to contain the bacon fat, as you'll need it for the recipe, too.
Lay the bacon slices flat on the parchment, leaving enough space between so they don't overlap.
Place the sheet in the preheated oven and cook for 25 to 30 minutes, or until crispy. The exact amount of cooking time depends on the thickness of bacon slices.
Remove from the oven and se aside to cool. When cool enough to handle, crumble the bacon into a bowl and set aside.
To the cream cheese and butter mixture, add the Gruyère or Cheddar cheese, jalapeños, and bacon grease. Mix well to combine. Refrigerate for 30 minutes to 1 hour, or until set.
Divide the mixture into 6 fat bombs and place them on a parchment-lined plate. If serving immediately, roll them in the crumbled bacon until well coated. If serving later, refrigerate without the bacon coating in an airtight container for up to 1 week. Roll the fat bombs in freshly cooked or reheated bacon crumbs just before serving.