Preheat oven to 375°F. In a large bowl, toss together blueberries, sugar, lemon juice, cornstarch and salt.
Make the topping by combining the chopped pecans, flour, oats, sugar, cinnamon, nutmeg and salt in a medium bowl. Use a pastry blender or 2 knives to work in the butter until topping resembles coarse meal.
Butter an 11 x 7 inch baking dish. Add blueberry mixture to baking dish. Top with crumb topping.
Bake for 35-40 minutes or until topping is golden brown and fruit is bubbling. Cool slightly and serve warm.
Notes
It goes without saying, but fresh blueberries make for a great crisp. I usually make this when blueberries are in season.
Don't over sweeten the blueberries. Remember the blueberries are the star here.
Cornstarch is an important ingredient in making the filling thicker so don't skip using it. You can use flour in a pinch, but cornstarch is better.
No crumb topping is complete without oats, but the secret ingredient here is the pecans which gives the crumb topping extra flavor and crunch.
Don't forget to top the blueberry crisp with some ice cream. While it is not required, the cold ice cream complements the warm crisp perfectly.