Pour 2 cups heavy whipping cream and 1 cup unsweetened almond milk into a medium saucepan. Heat over medium heat, stirring occasionally, for 5 minutes until steam rises and small bubbles form around the edges (do not boil). It should feel hot to touch but not be actively bubbling. Checkpoint: You are ready to move on when the mixture steams gently and reaches about 180°F on a thermometer.

In a separate medium bowl, add 5 room-temperature egg yolks, 0.75 cup monk fruit sweetener, and 0.25 teaspoon sea salt. Whisk vigorously for 2-3 minutes using an electric mixer or by hand until the mixture becomes pale yellow and thick (it should leave a trail when you lift the whisk). Checkpoint: You are ready to move on when the mixture is noticeably lighter in color and slightly foamy.

Slowly pour the hot cream mixture into the egg yolk mixture one small ladle at a time, whisking constantly between each addition for at least 30 seconds. This gradual process (called tempering) prevents scrambling the eggs. Continue until all hot cream is incorporated. The mixture should now be warm and pale. Checkpoint: You are ready to move on when the entire hot cream has been whisked into the yolks and the mixture is uniform and smooth.

Pour the combined custard back into the saucepan. Place over low heat and stir constantly with a rubber spatula, scraping the bottom and sides, for 8-10 minutes until the mixture reaches 160°F on a food thermometer or coats the back of a wooden spoon (run your finger across the spoon; the custard should leave a clear trail). The mixture should feel hot but never simmer or bubble. Checkpoint: You are ready to move on when the custard reaches 160°F and coats a spoon thickly.

Remove the saucepan from heat immediately. Stir in 2 tablespoons unsalted butter (cut into small pieces) and 2 teaspoons pure vanilla extract. Stir for 1-2 minutes until the butter melts completely and the mixture is smooth.

For the smoothest texture, pour the custard through a fine-mesh sieve into a clean bowl, pressing gently with the back of a spoon to catch any cooked egg particles or lumps. This step takes 2-3 minutes. Checkpoint: You are ready to move on when all custard has passed through the sieve and the mixture is perfectly smooth.

Cover the bowl with plastic wrap, pressing it directly onto the surface of the custard to prevent a skin from forming. Place in the refrigerator and chill for at least 4 hours, or preferably overnight (up to 24 hours). The colder the custard, the faster it will churn. Checkpoint: You are ready to move on when the custard is completely cold and no warmth remains when you touch the outside of the bowl.

If using an ice cream maker: Pour the cold custard into your ice cream maker and churn according to manufacturer's instructions (typically 20-25 minutes). The mixture should go from liquid to soft-serve consistency with a thick, creamy texture. Transfer the soft-serve ice cream to a freezer-safe container (or store-bought ice cream container) and freeze for at least 4 more hours until scoopable. Checkpoint: You are ready to move on when the ice cream reaches soft-serve consistency and pulls away from the sides of the machine.

If using no ice cream maker: Pour the cold custard into a 9-by-5-inch loaf pan or similar freezer-safe container. Freeze for 30 minutes until slushy around the edges. Remove and stir vigorously with an electric mixer for 2-3 minutes, breaking up ice crystals thoroughly. Return to freezer. Repeat this stir-and-freeze cycle every 30 minutes for 2.5-3 hours total until the mixture reaches soft-serve consistency. For extra smoothness, stir in 0.5 teaspoon xanthan gum before the first freeze cycle (whisk it into the cold custard completely first). Final freeze in a container for 4 hours until firm. Checkpoint: You are ready to move on when the ice cream is thick, creamy, and scoopable.

Let the frozen ice cream sit at room temperature for 5-10 minutes before scooping (this makes scooping easier). Serve immediately in chilled bowls or cones. Leftover ice cream can be stored in an airtight freezer-safe container for up to 2 weeks.