The Engineer Recipe

Chill your jars in the fridge for 10 minutes so the chocolate sets faster once applied.

Melt the chopped chocolate with the tablespoon of oil in a heatproof bowl over a simmering pot of water (double boiler) or in 20–30 second bursts in the microwave, stirring until smooth.

Pour the Oreo and mint cookie crumbs into a shallow bowl and mix to combine.

Dip the mouth of each chilled jar into the melted chocolate, tapping gently to remove excess, then immediately press the chocolate rim into the cookie crumb mixture so crumbs adhere. Set the jars upright on a parchment-lined tray and refrigerate until chocolate is firm, about 10–15 minutes.

Optional: Use a small spoon to drizzle a thin layer of warm chocolate sauce inside the bottom and partway up the jar for a chocolate-lined interior. Return jars to chill briefly so the drizzle firms.

Place a mixing bowl and whisk or beaters in the freezer for 5 minutes to chill (helps cream whip better).

Pour the cold heavy cream into the chilled bowl. Add the cocoa powder, powdered sugar, and vanilla extract.

Whip on medium-high speed with an electric mixer (or by hand) until soft-medium peaks form. Taste and adjust sweetness if desired. Transfer to a piping bag fitted with a large star tip (or a zip-top bag with corner snipped) and refrigerate until ready to assemble.

If the iced brownie is refrigerated or too firm, let it sit at room temperature 10–15 minutes so it’s slightly softer but not melted.

If you want extra icing sheen, lightly warm the top of the brownie under a low broiler for 5–8 seconds or microwave for 3–5 seconds—just enough to soften, not melt entirely. Immediately press extra sprinkles into the icing so they stick.

Cut the brownie (if necessary) into a size that will rest dramatically on the jar rim — typically a large square or triangle about 3–4 inches across. Reserve on a small plate until assembly.

Scoop the slightly softened mint chip ice cream into the prepared jars, dividing evenly (about 1/2 cup per jar if making 4 jars). Pack gently to avoid large air pockets.

If using, add a drizzle of warm chocolate sauce between ice cream layers or on top for extra chocolate pockets.

Press a whole or halved mint cookie into the side or top of the ice cream in each jar for garnish.

Pipe a generous swirl of the chocolate whipped cream on top of each jar of ice cream, forming a tall mound that can support the brownie.

Sprinkle black and green sprinkles and mini chocolate chips over the whipped cream.

Carefully rest the prepared iced brownie on top of the whipped cream so it sits partly on the rim and partly over the whipped peak (the whipped cream will help support it). If the brownie is too heavy, cut to a smaller size or press it in gently so it nests into the cream.

Add one or two additional mint cookies standing upright beside the brownie for visual height and texture.

Serve immediately with long spoons and napkins. If you must hold them for later, refrigerate upright for up to 30 minutes; beyond that the ice cream will soften and the assembly may slump.