Instructions

Preheat oven to 375°F. Brush a 9x13-inch baking pan with melted butter. Line pan with parchment paper, letting it slightly overhang on all sides. Butter the parchment paper and set aside.

Crust:

Put butter and brown sugar into the bowl of an electric mixer fitted with the paddle attachment; mix on medium speed until the mixture is light and fluffy. You will mix for about 2 minutes. Mix in salt and then add gluten-free flour, 1 cup at a time, mixing until fully incorporated after each addition. Continue mixing the dough until it begins to come together in large clumps.

Press dough about 1/4-inch thick into prepared pan. Pierce the dough with a fork. Chill until firm, about 20 minutes. Bake until golden brown, 20 to 22 minutes. Transfer to a wire cooling rack let it cool completely. Reduce oven to 325°F.

Filling:

Put the butter, brown sugar, honey, granulated sugar, and heavy cream in a saucepan over high heat. Bring mixture to a boil, stirring constantly until the mixture coats the back of a spoon, about 1 minute. Remove pan from heat and pour filling into the cooled crust.

Bake until filling bubbles, about 15 to 20 minutes. Carefully transfer to a wire cooling rack and let it cool completely. Run a paring knife around edges of the pan and invert onto the cooling rack. Invert again onto a cutting board. Use a sharp knife to cut into 1-by-3-inch bars.