Place butter, brown sugar, flour, cinnamon and salt in a food processor.
1 cup butter, 1 cup brown sugar, 2 cups flour, 2 teaspoons cinnamon, ½ teaspoon salt
Pulse until mixture is combined and crumbly.
Add oats and pulse until combined.
1 cup oats
Divide mixture into two equal parts. Place one half into a greased 11 X 7 inch baking dish. Pat crust firmly down. Reserve other half for top.
Filling
Place water, berries, sugar, corn starch, lemon zest, lemon juice and salt in a saucepan. Heat over medium heat, stirring often, until simmering. Remove from heat.
Bake in a preheated 325 degree oven for 40 minutes.
Allow bars to fully cool before cutting and serving. Cut into 12 equal pieces.
Notes
Tips for making Blueberry Crumb Bars
Use old fashioned oats
Cut butter into small pieces before adding to food processor
Add a bit of water to the bottom of the pot prior to adding blueberry filling ingredients. This helps prevent scorching before the blueberry juices start flowing.
Allow bars to cool before cutting and serving
Fresh or frozen berries may be used in this recipe