Preheat oven to 400°F / 200°C and lightly grease a nonstick muffin tin or line with paper liners.
In a large mixing bowl, mix together oat flour, monkfruit erythritol sweetener, baking powder, baking soda and salt until combined.
In another mixing bowl, mix together egg, low-fat sour cream, olive oil, milk and lemon juice until combined.
Add dry mixture to the bowl with the wet mixture and stir until just combined. Do not over-mix.
Gently stir in blueberries.
Transfer batter to lined muffin tin.
Bake for 25 minutes or until an inserted toothpick comes out clean.
Transfer muffins to a cooling rack and let cool completely before storing in an airtight container. Enjoy!