Preheat oven to 350 degrees F

Place the blueberries into a colander and rinse with cold water. Drain well and pick out any stems or bad berries.

Pour the blueberries into a medium bowl and add lemon juice, zest, sugar, cinnamon, salt and flour and toss to coat.

Spray a 9X9 casserole dish with kitchen pan spray then pour in the filling.

In a medium bowl, mix flour, both sugars, salt, rolled oats, slivered almonds and almond extract and toss.

Remove the cold butter from the refrigerator and cut into four long strips. Then turn sideways and cut small pieces from one end to the other and add to the bowl.

Use your hands and work the butter into the mixture until the butter pieces are about pea size. Does not have to be exact.

Sprinkle the topping over the filling, spray the top with a coating of kitchen pan spray then bake for 40 minutes.

Turn on broiler and brown the top for about a minute.

Serve warm with vanilla ice cream.