In a bowl, using an electric blender or whisk, blend together eggs, yolks, and sugar for about 5 minutes.

Then, in a saucepan, heat milk and cream over medium heat. Do not let the mixture boil. Take off the heat before it begins to boil.

Slowly pour 1 cup of the heated milk mixture into the egg mixture, whisking rapidly to prevent the eggs from cooking.

Once the milk is whisked into the eggs, pour the egg mixture into the saucepan with the remaining milk mixture, while whisking.

Heat the mixture over medium heat, stirring constantly, until the custard becomes thick enough to coat the back of a spoon. Turn off heat.

Pour the custard into a bowl and cover with plastic wrap. Press the plastic wrap down so that it touches the surface of the custard. Chill in the refrigerator until cool.

Once the custard is completely chilled, pour into the ice cream maker bowl with the vodka. Follow the manufacturer's instructions. Halfway through the churn time, pour in the 1/2 cup of chilled coffee. When the ice cream has a few minutes left of churning, add in the chocolate chips.

Store in an airtight container in the freezer. Freeze ice cream for a few hours before serving. Makes about 1 quart.