Browned Butter Oatmeal Trail Mix Cookie Bars

1 cup unsalted butter

1 cup light brown sugar, packed

1/2 cup granulated sugar

2 large eggs

1 Tbsp. vanilla extract

2 cups old-fashioned, rolled oats

1 1/2 cups all-purpose flour

1 tsp. baking powder

1 tsp. baking soda

1/2 tsp. sea salt

1/2 tsp. ground cinnamon

2/3 cup raisins

2/3 cup roasted peanuts

2/3 cup candy-coated chocolate pieces

1 tsp. coarse/flaky sea salt

1. Start by browning the butter. In a medium skillet over medium heat, place the butter. Let it melt completely and begin browning. It will pop and sizzle as the water from the butter evaporates and the solids begin to brown. Leave it mostly undisturbed, except to swirl the pan once or twice. The butter is browned when it smells very toasted and the popping noise has almost subsided. Keep a close eye on this process so that you don’t burn it! Once it’s done, remove it from the heat and set aside to cool for about 10-15 minutes. 
2. Preheat oven to 350 degrees F. Lightly grease a 9x13-inch baking pan, and set aside. 
3. To a large mixing bowl, add the cooled browned butter, brown sugar, granulated sugar, eggs, and vanilla extra. Stir until well-combined. 
4. To the mixing bowl, add the oats, flour, baking powder, baking soda, salt, and cinnamon. Stir until the dry ingredients are just incorporated. 
5. To the dough mixture, add the raisins, peanuts, and candy-coated chocolate pieces. Fold in gently until evenly distributed throughout the dough.
6. Transfer the cookie dough to the prepared 9x13-inch pan. Press it into the pan in an even layer.
7. Bake at 350 degrees F for 25-28 minutes, or until golden brown. Remove from the oven and immediately sprinkle with the coarse sea salt. 
8. Let the cookie bars cool completely in the pan before cutting. 
9. Store cut cookie bars in an airtight container at room temperature for up to 5 days.