Preheat oven to 375 degrees F.
Toss blueberries, cornstarch, sugar and a pinch of salt together in a bowl.
Combine flour, oats, brown and white sugar, cinnamon, nutmeg and pecans in a bowl. Add butter and pinch into chunks. Mix until it looks crumbly.
Add the blueberries into a 2-quart baking dish. Top evenly with the crumb mixture. Bake for 40 minutes. Serve with ice cream and whipped cream.