April 23 is National Picnic Day. Make these Blackberry-Oat Crumble Bars courtesy of Southern Living for a perfectly delicious and portable picnic treat. Yields 24 bars.
Preheat oven to 350 degrees Fahrenheit. Stir together 6 cups rolled oats, 2 1/4 cups packed light brown sugar, 2 1/4 cups all-purpose flour, 2 cups melted butter, 1 teaspoon kosher salt and 1 teaspoon baking soda. Remove 3 cups of the oat mixture and set aside.
Press remaining oat mixture in an even layer on a buttered 12×17-inch rimmed baking sheet. Bake until golden brown, approximately 20 minutes. Cool completely, for around 30 minutes.
Meanwhile, stir together 9 cups blackberries, 1 cup sugar, 1/2 cup lemon juice and 1/4 cup corn starch in a large saucepan. Cook over medium until syrup thickens and bubbles, about 8 minutes. Pour over prepared crust and top with reserved crumble. Bake at 350 degrees Fahrenheit until the topping is golden brown, around 30 to 35 minutes.