Fudgy Zucchini Brownies

6 ounces gluten free flour blend (1 1/3 cup)
1/2 tsp salt
1/2 tsp xanthan gum
1 tsp stevia
4 ounces semisweet chocolate, chopped coarse
8 Tblsp unsalted butter, cut into 8 pieces
3 Tblsp unsweetened cocoa powder
3 large eggs
2 cups grated zucchini
1/4 cup sugar or coconut sugar
2 tsp vanilla extract

1. Make foil sling for 8-inch square baking pan by folding 2 long sheets of aluminum foil so each is 8 inches wide. Lay sheets of foil in pan perpendicular to each other, with extra foil hanging over edges of pan. Push foil into corners and up sides of pan, smoothing foil flush to pan; spray with vegetable oil spray.
2. Whisk flour, salt, and xanthan gum together in bowl; set aside. Microwave chocolate, butter, and cocoa in bowl at 50 percent power, stirring often, until melted and smooth, 1 to 3 minutes. Let mixture cool slightly.
3. Blend eggs, zucchini, sugar and vanilla together in blender. Whisk in cooled chocolate mixture. Stir in flour mixture using rubber spatula and mix until well combined. Scrape batter into prepared pan and smooth top with spatula. Cover pan with plastic wrap and let batter rest for 30 minutes.
4. Adjust oven rack to middle position and heat oven to 350 degrees. Remove plastic and bake until toothpick inserted in center comes out with few moist crumbs attached, 45 to 55 minutes, rotating pan halfway through baking.
5. Let brownies cool completely in pan on wire rack, about 2 hours. Using foil overhang, lift brownies out of pan. Cut into squares and serve. (Brownies are best eaten on day they are baked but they can be cooled and placed immediately in airtight container and stored at room temperature for up to 2 days.)