These ooey-gooey treats taste like a twist between blackberry cobbler and a bar cookie. The recipe, which was created by the chefs at Blackberry Farm, an award-winning luxury hotel and resort in eastern Tennessee, is a wonderful way to show off tangy, in-season blackberries. Make this recipe in the height of summer, when berries are at their best. The crust recipe, made with light brown sugar, rolled oats, flour, and butter, doubles as a streusel topping that toasts up beautifully in the oven. (The crust can be made a day in advance. Press it into the pan, cover with plastic wrap, and refrigerate.) The filling, a simple take on blackberry jam, can also be made a day in advance. Warm the mixture on the stovetop or microwave before pouring over the crust to make sure it spreads evenly. “These oat bars are a Blackberry Farm classic,” says Sarah Steffan, executive chef of The Dogwood restaurant at Blackberry Farm. “The recipe changes a lot with the seasons—we do it with peaches, strawberries, apples, you name it. The secret? Lots of butter.”
6 cups regular rolled oats
2 1/4 cups packed light brown sugar
2 1/4 cups all-purpose flour
2 cups unsalted butter, melted, plus more for pan
1 teaspoon kosher salt
1 teaspoon baking soda
9 cups fresh blackberries
1 cup granulated sugar
1/2 cup fresh lemon juice (from 3 lemons)
1/4 cup cornstarch
How to Make It
Prepare the Crust: Preheat oven to 350°F. Stir together oats, brown sugar, flour, butter, salt, and baking soda. Remove 3 cups of the oat mixture, and set aside. Press remaining oat mixture in an even layer in an aluminum foil-lined and buttered 12- x 17-inch rimmed baking sheet. Bake in preheated oven until golden brown, about 20 minutes. Cool completely, about 30 minutes.
Prepare the Filling: Stir together blackberries, sugar, lemon juice, and cornstarch in a large saucepan. Cook over medium, stirring occasionally, until syrup thickens and is bubbly, about 8 minutes. Pour over prepared Crust, and crumble reserved 3 cups oat mixture evenly over Filling. Bake at 350°F until topping is golden brown, 30 to 35 minutes. Cool completely, about 2 hours. Cut into 24 pieces.