NUTELLA-BROWN BUTTER CRISPIES

Steps:

• Lightly butter a 13x9" baking dish, then line with parchment paper, leaving a 2" overhang on long sides. Lightly butter parchment. Cook 3/4 cup butter in a large pot over medium heat, swirling, until butter foams, then browns (be careful not to let it burn), 5-7 minutes. Add marshmallows and salt. Reduce heat to low and cook, stirring constantly, until marshmallows are melted and mixture is smooth, about 3 minutes. Add Nutella and stir until completely incorporated into marshmallow mixture, about 2 minutes.
• Remove pot from heat and add half of puffed rice to marshmallow mixture; stir with a nonflexible heatproof spatula or wooden spoon, scraping bottom of pot and folding, until cereal is coated. Add remaining cereal and fold until mixture is homogenous. (It's a lot of cereal, so you'll need to exert some effort.) If mixture is too stiff, heat over low while continuing to fold in cereal. Scrape into prepared pan; let cool slightly, then cover with a sheet of parchment paper. Press down firmly to make an even, compact layer (you want the top to be as flat as possible; a smaller pan, like a loaf or an 8x8" pan, works great for this). Cover crispies loosely with plastic and let sit until cool, about 2 hours.
• Just before serving, using parchment paper overhang, lift crispies out of pan and place upside down on a cutting board; remove parchment. Using a serrated knife, trim about 1/2" from all sides to make a squared-off rectangle, then cut into a 6x4 grid to make 24 squares. Place crispies on a wire rack, spacing at least 1" apart.
• To make half the crispies red, if desired, pulse freeze-dried strawberries in a food processor until finely ground; add luster dust and pulse just to combine. Using a fine-mesh sieve, dust 12 squares with strawberry powder, then, using a dry, clean sieve, dust remaining 12 squares with powdered sugar. Or feel free to dust all 24 squares with powdered sugar instead.
• Do Ahead
• Crispies can be made 1 day ahead. Leave in pan. Store tightly wrapped at room temperature. Cut into squares and coat just before serving.