Cook the bacon in a large skillet over medium heat until crisp, about 8 minutes.
Transfer to paper towels, reserving rendered bacon fat in the skillet.
Strain the rendered bacon fat through a fine mesh sieve to remove any charred bits.
Return 2 tablespoons of the strained bacon fat to the skillet and warm over medium heat.
Whisk in the flour to form a roux.
Cook the roux to a golden brown, stirring often, about 2 minutes.
In a separate bowl, combine espresso, milk, and cream together.
Gradually add the milk mixture to the roux, whisking constantly.
Add the salt, pepper, and reserved bacon.
Simmer, stirring often, until thickened, 3-5 minutes.