At McPartlan’s Corner (669 Wehrle Drive, Amherst, 632-9896), you can tell it’s almost Christmas when the Tom & Jerry bowl comes out. It has been a standard at the family eatery for more than 30 years.

Mike McPartlan mixes each three-quart batch of the whipped-egg alcoholic concoction by himself, the same way his Uncle Jamie showed him. The holiday tradition “falls on my shoulders,” he said. “I guess it’s good to be consistent in the restaurant business.”

He separates a half-dozen eggs, and beats the yolks into a batter with cinnamon, sugar, nutmeg and a dash of vanilla. Then he whips the whites into a meringue, which he folds, ever so carefully, into the batter.

Then he’s ready to make the drink. He pours a measure of drink base into a 7.5-ounce Tom & Jerry cup with an ounce of rum. Piping-hot water is trickled into the cup, “cooking” the batter. Then he floats another three-quarters of an ounce of brandy on top. That’ll be $4.95.

“I won’t say it’s a secret recipe, but it’s an esoteric art,” McPartlan said. “It’s a lot of work, but if it brings ’em in the door it’s worth it, I always say.”

That it does. “We have people who I don’t see 11 months out of the year,” he said. “As soon as the Tom & Jerrys start, they’re in three times a week during the holiday season.” McPartlan expects to have them every day through New Year’s, and weekends through February.

– Andrew Z. Galarneau