Instructions

1. Heat oven to 350 degrees F. Coat a 9 by 13 baking dish with cooking spray. Fill a large metal bowl half-way with ice and water.
2. Melt butter in a small saucepan over medium-low heat. Cook, swirling the pan occasionally until the butter is completely melted and the milk solids are starting to brown, about 5 minutes. Remove from heat and set saucepan in the prepared ice bath to stop the butter from over browning. Let sit a minute or two just until room temperature. When butter is cool, but not re-solidified, remove from the ice bath and let sit.
3. Whisk flour, cocoa powder, baking soda and salt in a small bowl.
4. Beat Greek yogurt and eggs with electric mixer in a large bowl or in a stand mixer with whisk attachment, until completely smooth. Very gradually beat in butter until smooth. Beat in chocolate, sugar and vanilla until smooth. If using a stand mixture switch to paddle attachment. Beat in flour mixture until smooth, scraping down sides and paddle as necessary. Scrape brownie batter into the prepared baking dish and immediately spread out until smooth. Scatter trail mix over the top of the batter. Bake until the center is puffed slightly and set, 20 to 22 minutes. Cool brownies in the baking dish until room temperature, about 1 hour. Drizzle chocolate over the cooled brownies.