Place oven rack in lower-middle third of oven and pre-heat oven to 375 degrees F.
Combine the granulated sugar, cornstarch and salt in a large bowl. Add the blueberries and toss gently to coat well.
Pour berries into an 8 x 8 inch ovenproof baking dish and sprinkle with the lemon juice.
In another large bowl, combine the flour, brown sugar, Nuthin’ But Datil, and ground cinnamon.
Add the cold butter to the bowl and use a pastry blender or 2 knives to cut the butter into the dry ingredients. Work the mixture lightly so that it doesn’t become oily.
Stir in the oats and pecans until small clumps form. You can use your fingers to gently work the mixture together,
Sprinkle this crumb mixture over the berries in your baking dish. The best way to do this is to mound the topping in the center of the dish and use your fingers to lightly move the topping out toward the edges of the pan. Don’t push the topping down into the blueberry mixture, or it will become soggy, and you won’t have a nice crisp topping.
Place in the oven and bake for about 30 minutes, until the topping is golden and the blueberry filling is bubbling around the edges of the pan.
Remove from the oven and cool for about 30 minutes.
Serve while still warm with Vanilla Bean ice cream or whipped cream.
