- 6 Tbsp. unsalted butter, plus more for pan
- 1 cup chopped nuts, such as walnuts, hazelnuts, and/or pecans
- ¾ cup creamy unsweetened almond butter
- ½ cup pure maple syrup
- 2 Tbsp. flaxseed meal
- 2 tsp. vanilla extract
- 1 tsp. kosher salt
- ½ tsp. baking powder
- 3 large eggs
- Preheat oven to 350°. Line an 8×8″ baking dish with a sheet of parchment paper, leaving an overhang on two sides. Grease parchment with butter.
- Cook nuts and 6 Tbsp. butter in a medium skillet over medium heat, swirling pan often, until butter foams, then browns, 5–6 minutes. Strain through a fine-mesh sieve into a large bowl; set aside nuts. Add almond butter, maple syrup, flaxseed, vanilla, salt, and baking powder to hot brown butter and whisk until smooth. Add eggs one at a time, whisking to incorporate after each addition. Vigorously whisk batter until glossy and smooth, about 1 minute. Stir in all but about 3 Tbsp. reserved nuts. Scrape batter into prepared pan and spread in an even layer. Top with remaining nuts.
- Bake blondies until top is puffed and lightly browned and a tester inserted into the center comes out with a few moist crumbs attached, 18–22 minutes. Let cool.
- Remove blondies from pan using parchment overhang. Cut into squares.