Oatmeal Fudge Bars

These decadent bars are full of pleasing textures and flavors. The crust tastes similar to a buttery caramel and the topping is buttery tasting with a slightly nutty flavor. The topping is chewy while the filling has a smooth under-baked brownie consistency. The filling is unbelievably rich and chocolaty, which will make you want more. Makes 16 bars.
Crust and Topping:
1 Cup (3 ounces) quick-cooking oats
1 Cup packed (7 ounces) light brown sugar
3/4 Cup (3 3/4 ounces) all-purpose flour
1/4 teaspoon baking powder
1/4 teaspoon baking soda
1/8 teaspoon table salt, about a pinch
8 Tablespoons (1 stick) unsalted butter, melted and cooled
Filling:
1/4 Cup (1 1 1/4 ounces) all-purpose flour
1 Cup packed brown sugar (1 3/4 ounces) light brown sugar
2 teaspoons instant espresso or instant coffee
1/4 teaspoon table salt
1 1/2 Cups (9 ounces) semisweet chocolate chips
2 Tablespoons unsalted butter
1 Large egg

1. Adjust an oven rack to the middle position and heat to 325 degrees F. Line an 8-inch square metal baking pan with two layers of aluminum foil, overlapping each other; lightly spray with nonstick vegetable oil.
2. For crust and topping: Whisk the oats, flour, baking powder, baking soda, and salt together in a large mixing bowl. Stir in melted butter until combined. Reserve 3/4 Cup of the oat mixture for the topping.
3. Sprinkle the remaining oat mixture into the prepared pan and press into an even layer, using your hands or the bottom of a measuring cup. Bake the crust until light golden brown, about 8-10 minutes. Cool on a wire rack for 1 hour.
4. For the filling: Whisk the flour, sugar, instant espresso, and salt together in a medium bowl. Melt the the chocolate chips and butter for1-3 minutes on 50% power, stopping occasionally to stir the mixture. Transfer the chocolate mixture to a large bowl and let cool slightly. Whisk in the egg, until combined; then stir in the flour mixture until just incorporated.
5. Adjust an oven rack to the middle position and heat to 325 degrees F. Spread the filling evenly over the cooled crust. Sprinkle the reserved oat topping. Bake the bars until a toothpick inserted into the center comes out with a few moist crumbs attached and the filling begins to pull away from the sides of the pan, 25-30 minutes, rotating the pan halfway through baking.

 

From The America's Test Kitchen Family Baking Book