Cut avocados in half, pit them and scoop the flesh carefully out of the shells. Put the shells in the freezer.
Blend together avocado flesh, almond milk, lemon juice, heavy cream and erythritol. Transfer the mixture to a bowl and place in the refrigerator for 5 hours to chill.
Process the mixture in an ice cream maker for 5-10 minutes according to the manufacturer's instructions.
Fill the avocado shells with ice cream, place in freezer for 2 hours and enjoy!