In a saucepan, combine 2% milk (reserve a few tablespoons) and evaporated milk. Heat gently until hot, but not boiling.
Mix the reserved milk with cornstarch to create a slurry. Add to the pot along with monk fruit sweetener, vanilla, and a pinch of salt.
Stir continuously over medium heat until the mixture thickens and starts to bubble (about 5–7 minutes).
Remove from heat. Cool the mixture quickly by placing the pot in a large bowl filled with ice water. Stir occasionally to prevent a skin from forming.
Once cooled, pour the mixture into your pre-frozen ice cream maker bowl.
Churn according to your machine’s instructions (usually around 30 minutes).
In the final minutes of churning, add crushed Biscoff cookies if using.
Transfer ice cream into a chilled storage container. Freeze until firm (1–2 hours).
Scoop and enjoy guilt-free!