2 sticks (1 cup) unsalted butter, melted and browned, cooled slightly
1 cup brown sugar, packed
1/2 cup granulated sugar
2 large eggs
1 large egg yolk
2 tablespoons milk
1 tablespoon vanilla extract
1 2/3 cups all-purpose flour
1 teaspoon baking soda
3/4 teaspoon salt
1/2 teaspoon ground cinnamon
2 cups rolled oats
1 1/4 cups chopped dark chocolate
1 teaspoon flaky sea salt, optional
- Preheat oven to 350 degrees F. Line a 9 x 13-inch baking pan with foil and lightly spray with nonstick cooking spray.
- In a medium-size bowl, whisk together melted browned butter, brown sugar and granulated sugar until well combined. Stir in vanilla. Add eggs and egg yolk, stirring after each addition until combined. Add milk and whisk to combine.
- In a separate bowl, whisk together flour, baking soda, salt and cinnamon. Add to wet ingredients in two additions, stirring after each addition until just combined. Stir in oats. Fold in chocolate chunks. Pour batter into prepared pan and smooth top.
- Bake for 25-30 minutes or until edges are set and golden and a toothpick inserted in the center comes out clean. Do not overbake. Cool completely before cutting. Sprinkle with flaky sea salt if desired.