In a medium sauce pan add blueberries, water, sugar, lemon juice, and sugar. Cook over medium heat stirring constantly until blueberries soften and filling thickens. Remove from heat and set aside.
In a medium bowl cut cold butter into small pieces.
Add oats, sugar, and flour.
Using either a fork or your fingertips mix all ingredients together until well combined and crumbly.
Preheat oven to 300 degrees F.
Spray a 9x13 baking dish with vegetable spray.
In a medium bowl combine butter, sugar, vanilla, and salt. Mix well.
Add flour and mix until it is just combined. Do not over mix.
Press dough evenly into the bottom of the baking dish and bake for 15 to 18 minutes or until well set.
Remove from oven and spread blueberry filling over the top of the crust.
Sprinkle crumb topping over the filling and return to the oven for 30 to 35 minutes.
Remove from oven and allow to cool.
While bars are cooling, combine the glaze ingredients together in a bowl and mix well.
When bars are cooled, drizzle the glaze over the top.
Cut and serve.
