This is one of the world's most forgiving desserts, and it's always a crowd-pleaser. The streusel acts as a crumbly press-in crust as well as a topping.
Why It Works
- An easy streusel topping comes together in minutes and doubles as the bottom crust.
- An infinitely variable recipe: Use the flours, jams, and nuts of your choice.
- Yield:Makes one 9- by 13-inch pan (can be cut into many bars of different sizes)
- Active time: 15 minutes
- Total time:3 hours
- 1 cup unsalted butter (2 sticks; 225g), melted, plus more for greasing pan
- 1 1/4 cups whole wheat flour (6 ounces; 175g) (see note)
- 1 cup all-purpose flour (5 ounces; 140g) (see note)
- 1 3/4 cups old-fashioned rolled oats (5.5 ounces; 160g)
- 1/2 cup granulated sugar (4 ounces; 110g)
- 1/2 cup light brown sugar (3 ounces; 85g)
- 1 1/2 teaspoons (6g) kosher salt
- 3/4 teaspoon (4g) baking soda
- 1 1/2 cups (350ml) apricot jam (see note)
- 1/2 cup (117g) walnuts, roughly chopped (see note)
Preheat oven to 350°F. Butter a 9- by 13-inch baking pan and line it with parchment paper so that the paper overhangs the long sides of the pan by about 1 inch.
In a large mixing bowl, stir together whole wheat flour, all-purpose flour, oats, granulated sugar, brown sugar, salt, and baking soda. Pour 1 cup melted butter over streusel mixture and stir until ingredients are evenly moistened.
Firmly press all but 3/4 cup of streusel in an even layer into prepared baking pan. Spread jam on top, leaving a 1/4-inch border all around. Press remaining streusel into clumps, add walnuts, and toss. Sprinkle walnut streusel all over jam.
Bake until top is golden brown, about 40 minutes. Transfer to a wire rack and let cool completely, about 2 hours.
Using overhanging parchment paper, lift dessert from baking pan and transfer to a work surface. Cut into bars. Bars can be stored at room temperature for up to 3 days.