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