Step 1: Heat the milk and cream
In a medium saucepan over medium heat, combine the 2 cups of heavy cream and 1 cup of whole milk. Stir gently until the mixture begins to steam and tiny bubbles form around the edges, but do not let it boil.

Step 2: Whisk the egg yolks and sugar
In a separate bowl, whisk together the 4 large egg yolks and ¾ cup granulated sugar until the mixture becomes thick and pale. This will take 2–3 minutes by hand or 1 minute using an electric hand mixer.

Step 3: Temper the eggs
To prevent scrambling, you need to slowly add hot liquid to the egg mixture. Gradually pour about 1 cup of the hot milk mixture into the egg yolks while constantly whisking. Once combined, pour the tempered egg mixture back into the saucepan with the rest of the milk and cream.

Step 4: Cook the custard
Place the saucepan back over medium heat. Stir constantly with a wooden spoon or silicone spatula until the mixture thickens enough to coat the back of the spoon—about 5–7 minutes. Do not let it boil. Remove from heat immediately once thickened.

Step 5: Add coffee and flavorings
Stir in the ¼ cup of cooled espresso or strong coffee, 1 tablespoon of instant coffee granules, 1 teaspoon of vanilla extract, and ¼ teaspoon of salt. Stir until the instant coffee is fully dissolved and everything is well incorporated.

Step 6: Chill the base
Pour the custard through a fine-mesh sieve into a clean bowl to remove any curdled bits. Cover the surface with plastic wrap, pressing it directly onto the custard to prevent a skin from forming. Refrigerate for at least 4 hours, preferably overnight, until completely cold.

Step 7: Churn the ice cream
Once chilled, pour the custard into your ice cream maker and churn according to the manufacturer’s instructions. This usually takes 20–30 minutes. The mixture should become thick and creamy. If using chocolate chips or crushed espresso beans, add them in the last 5 minutes of churning.

Step 8: Freeze until firm
Transfer the churned ice cream into an airtight container. Press plastic wrap or parchment directly onto the surface to prevent ice crystals. Freeze for at least 4 hours before serving.