1.Preheat oven to 350 degrees.
2.Clean and dry the mason jars. Place 4 small (8 ounce) mason jars on a baking that’s been lined with foil. Set aside.
3.Rinse blueberries with cold water and pat dry with paper towels.
4. Combine brown sugar, oats, flour, salt in a medium mixing bowl.
5.Use hands to break and mix in the cold butter until crumbly.
6.Divide the mixture between 4 jars.
7.Add fresh blueberries to the 3/4 point.
8.Top with remaining crumble.
9.Bake for 30-35 minutes.
10.Allow to cool to warm or at room temperature. Top with ice cream, whipped cream or Greek Yogurt. Enjoy!