INGREDIENTS
Cooking spray
4 tsp
cornstarch, divided
2 tbsp
brown sugar
1/2 tsp
vanilla extract
1 lb
fresh or frozen blueberries
2 1/4 oz
all-purpose flour (about 1/2 cup)
1/2 cup
packed brown sugar
1/4 cup
old-fashioned rolled oats
3 tbsp
chopped walnuts
2 tbsp
cornmeal
1/2 tsp
salt
1/4 tsp
ground cinnamon
1/4 cup
chilled butter, cut into small pieces