Place a saucepan over a medium heat
Add the vinegar, pepper, nutmeg, cinnamon, cayenne pepper, and bay leaf to the saucepan and simmer for 15 minutes until reduced
Remove the bay leaf and set aside to cool
Place the eggs in a stand mixer with a whisk attachment and turn to a medium speed
Add the vinegar mixture to the eggs until combined
Very slowly add the hot butter into the mixer until the sauce is glossy
Season and serve immediately