How to Make It
To prepare caramel sauce, combine 3/4 cup granulated sugar, corn syrup, and 2 tablespoons water in a small saucepan; cook over medium-high heat 7 to 8 minutes or until mixture is amber colored, stirring frequently. Remove from heat; add half-and-half, stirring with a whisk until blended (mixture will bubble). Stir in salt.
Preheat oven to 350°.
To prepare brownie batter, weigh or lightly spoon sorghum flour and rice flour into dry measuring cups; level with a knife. Combine sorghum flour, rice flour, cocoa, and next 4 ingredients (through 1/2 teaspoon sea salt) in a medium bowl; stir with a whisk.
Combine butter and bittersweet chocolate in a large microwave-safe bowl. Microwave at HIGH 1 minute or until melted, stirring every 30 seconds. Add 1/2 cup granulated sugar, brown sugar, milk, vanilla, and eggs, stirring until well blended. Gradually add flour mixture, stirring until moist.
Spread half of batter in an 8-inch square metal baking pan coated with cooking spray; pour caramel sauce over batter in pan. Drop remaining batter by tablespoonfuls onto caramel sauce; swirl gently with the tip of a knife. Bake at 350° for 30 minutes or until brownies are set. Cool completely on a wire rack.
Gluten-Free Baking; The Food Lover's Gluten-Free Cookbook