Lakanto, Swerve, or Erythritol. I stick toLakanto andSwerve which are a 1:1 swap with traditional sugar. If using a different brand of Erythritol, keep in mind it's 70% as sweet as sugar, so you may need to add more to taste.
Milk. I swap between unsweetened light almond or coconut milk.
Nutritional information is based on 1 shake if you divide this recipe into 2. It doesn't include whipped cream or chocolate syrup.