1 cup of heavy cream
2 cups whole milk
1/4 cup espresso coffee grounds (coarsely ground)
1 tablespoon espresso powdwer
5 egg yolks
3/4 cup sugar
1 tablespoon of Kahlúa
Get the coursest ground coffee you can—percolator ground or more course is best. Each time you pour the mixture from a saucepan or bowl more of the finer grounds will have the opportunity to be left behind. Combine the cream, milk, coffee grounds and espresso powder in a saucepan and heat over medium heat until just simmering. Remove from heat and pass mixture through a chinois or fine mesh sieve.
Beat five egg yolks and slowly add the sugar while mixing at medium speed until color lightens to a light yellow and becomes fluffy. Use a spatula to scrape the bottom of the bowl during mixing.
With the mixer on low, slowly add the hot milk and cream mixture to the egg yolk and sugar mixture. Mix until blended and then return this mixture to the saucepan. Heat the custard mixture over medium heat, stirring constantly, until mixture reaches about 165 °F.
Pour the custard mixture through a chinois or sieve into a bowl. Place bowl with gelato base into an ice bath or refrigerator. Once the mixture has chilled to room temperature you can add the Kahlúa. Return to ice bath/refrigerator and chill until mixture reaches 45 °F. Freeze according to your ice cream/gelato maker's instructions and transfer to a container. Let ripen in freezer for several hours before serving.