In a small bowl, whisk the powdered sweetener into the egg yolks. Set aside.
In a small pan, heat the half n half over medium heat. Be careful not to boil or burn the cream.
When the cream is warm to the touch, about 2 or 3 minutes later, remove it from the heat. Use a tablespoon to temper the eggs by slowly whisking in 1 tablespoon of the warm cream into the eggs. Repeat this step 2 more times to fully temper the eggs.
Slowly add the egg yolks to the cream and whisk until smooth and silky. Add the collagen and whisk again until it is fully dissolved.
Line the ramekins on a baking sheet with a rim. Carefully fill each ramekin with the custard. They should be about 2/3 full.
Extend the oven rack so that it is exposed outside of the oven. Carefully place the baking sheet on the rack. Add water to the sheet pan so that the ramekins are halfway covered. This amount will vary depending on the size of your ramekin. Be careful not to get water in the pots.
Carefully slide the oven rack into the oven. Bake for 25 minutes. The centers should be set.
Let the custards chill on the counter for 30 minutes before serving or chilling.
Notes
Optional- Reserve egg whites to make a meringue topping for the custards. Add half of the egg whites to a small mixing bowl or the bowl of a stand mixer. Whisk on high until the egg whites pass the "foamy" stage and stiffen, about 4 or 5 minutes. Slowly add 2 or 3 tablespoons of granular sweetener and mix until incorporated, about 30 seconds. Spread the meringue on top of each ramekin, making sure to get it all the way to the edge. Place on the middle rack under the broiler and cook until browned and set, about 2 or 3 minutes.