Combine the half and half , heavy cream and ground coffee in medium saucepan. Heat over medium heat stirring occasionally. Bring the mixture to a simmer then remove from heat and steep for about 10 minutes. Strain mixture through a fine mesh strainer into a bowl. Discard grounds. Set cream mixture aside.

Whisk the egg yolks in a medium bowl until light in color and smooth. Add the sugar and salt slowly and whisk to combine. Add the cream mixture to the egg mixture in small amounts until you have included about half the cream mixture. Whisk in the remainder of the cream mixture and return to the saucepan over low heat. Cook, stirring often until mixture reaches 175 degrees. At this stage the mixture will be slightly thickened and will coat the back of a spoon. Remove from heat and pour into container. Let cool on counter for 30 minutes, then place in refrigerator overnight.