Lightly crush espresso beans by placing them in a bag and using a rolling pin, or pulse them two or three times in a coffee grinder, just to break the beans open.

Transfer to a small pot, add heavy cream, milk, sugar and vanilla bean and bring just to a simmer over medium heat, stirring to dissolve sugar.

Remove pot from the heat, cover and set aside for 30 minutes.

Preheat the oven to 300°F.

Remove vanilla bean, rinse and set aside.

Strain espresso bean mixture through a fine mesh strainer into a bowl, discarding solids.

Whisk yolks in a medium bowl until frothy then add about 1/2 cup of the hot milk mixture while whisking constantly to temper the yolks.

Pour the warmed yolk mixture back into the hot milk mixture while whisking constantly until well combined.

Strain one more time through a fine mesh strainer, discarding solids.

Halve vanilla bean lengthwise, scrape out the seeds and whisk into the yolk mixture along with the vanilla extract and salt; discard vanilla bean pod.

Arrange eight (6-ounce) ovenproof ramekins, bowls or teacups in a large, deep baking dish. (Use two baking dishes to avoid crowding, if needed.)

Divide the yolk mixture evenly between the cups then carefully pour enough hot water into the baking dish to reach about two-thirds of the way up the sides of the ramekins.

Bake until just set in the middle, 30 to 40 minutes, then set aside to let cool in the water bath.

Once cool, remove ramekins from water, cover individually with foil or plastic wrap and chill for at least 2 hours before serving.

Garnish with chocolate-covered coffee beans, if you like.