Preheat oven to 390ºF. Prepare 4 small (120 grams) ramekins by brushing their interiors with the soft butter.
Whisk the eggs, egg yolks, and cream together, and combine with the cheese, flour, half the chives, pepper, and nutmeg in the jar of a blender. Process at high speed. Divide the mixture between the ramekins.
Place the ramekins in a water bath with the water filled two-thirds the height of the ramekins. Cover the ramekins with a piece of parchment paper and bake until firm, about 35 minutes.
Let the ramekins rest, out of the water bath, for a couple of minutes before unmolding.
Before serving, cook the bacon in a frying pan until hot, but not crisp. Drain briefly.
Unmold the custards on individual serving plates. Divide the bacon over the "flans" (custard). Sprinkle the remaining chives over the tops.