Prep: Spray a 9×9 metal pan with nonstick spray and line with parchment paper. Read through the recipe and get all your equipment (saucepan, whisk, spatula, etc.) and your ingredients ready before you begin.

Make the Caramel: Add the sugar to a medium saucepan. Cook over medium heat, stirring frequently. After a few minutes, the sugar will melt into a coppery-caramely-colored liquid. Reduce the heat slightly, and add the butter, whisking constantly until it's completely melted. Remove the pan from the heat and slowly add the heavy cream, whisking as you add it. Return the pan to medium heat, and whisk in the flour and salt until the flour has completely disappeared. Cook, stirring constantly, until the caramel reaches a temperature of 235℉.

Divide & Freeze the Caramel: Portion out ⅔ of this caramel mixture and pour it into your parchment paper lined pan. Pop this in the freezer while you make the brownie batter.

Start the Brownie Batter: Preheat your oven to 350℉. Melt together the butter and chocolate in a medium bowl, in 30-second intervals, stirring between each until completely smooth. Whisk in the vegetable oil and cocoa powder. Set aside to cool.

Finish the Brownie Batter: In a large mixing bowl, add the eggs, egg yolk, and granulated sugar. Whisk for about 1-2 minutes, until the sugar is fully dissolved. Next, whisk in the powdered sugar, vanilla, and salt. Then, check that the chocolate mixture is at room temperature, and whisk it into the bowl of eggs and sugar. Fold in the flour & espresso powder, then the chocolate chips.

Assemble: Spray your now room temperature 9x9 pan with nonstick spray and line with a fresh piece of parchment paper. Spread half of the brownie batter into your pan. Lay the frozen sheet of caramel on top, then cover with the remaining batter. Dollop the extra caramel all over the batter, then swirl with a butter knife.

Bake: Bake the brownies for 42 to 50 minutes. When done, the edges will appear set and the center will have a bit of a wobble. A toothpick inserted into the center of the brownies should pull out moist crumbs, not wet batter.

Serve + Store: Let the brownies cool in the pan, on a cooling rack, for at least 45 minutes before slicing. Slice and enjoy while still warm!