Place the blueberries, water, lemon juice, and stevia in a small saucepan and mix gently. Heat the mixture over low heat.
Cook, stirring occasionally with a wooden spoon, until the blueberries are very soft and starting to burst. This should take 10-15 minutes, depending on the level of heat you use.
Remove the saucepan from the heat. Allow the compote to slightly cool and thicken for about 2 minutes. Serve alone in dessert bowls or as a topping.
Video
Notes
There's no need to add powdered sugar. Powdered sugar contains cornstarch that acts as a thickener. But I use just a touch of sweetener plus some lemon juice, with wonderful results. The compote is perfectly thick and syrupy.
You can keep the leftovers in an airtight container in the fridge for 3-4 days. You can enjoy them cold, straight out of the fridge, or gently reheat them in the microwave, covered, at 50% power. To freeze it, I suggest freezing it in small containers or an ice cube tray. This will enable you to defrost a small amount each time.