Spray a 9×9 baking dish with cooking spray. Line with parchment paper.: The sound of the parchment sliding into the dish signals that the pan is ready, and you should notice a slight cling as it fits. Lining with parchment ensures clean edges and easier removal when the fudge sets, which matters for presentation. A common mistake is skipping the parchment or skipping the spray, leading to fudge that sticks and tears when you try to lift it. Make sure the parchment extends over the edges so you can lift the whole slab once cooled.
Combine butter, sugar, and evaporated milk in a heavy bottomed saucepan.: As these ingredients meet in the pan you'll notice the butter starting to soften and the sugar settling into the milk, a muted sizzle may appear as the fat heats. Using a heavy bottomed saucepan matters because it distributes heat evenly, preventing hot spots that cause burning. If your pan is thin you risk scorching the sugar while still stirring. Take time to stir gently at the beginning so the butter melts uniformly into the evaporated milk .
Bring to a boil over medium heat, stirring frequently.: Watch for tiny bubbles forming around the edges and a rolling movement toward the center, that is your cue that the mixture is transitioning. The rhythmic sound of frequent stirring helps dissolve granulated sugar and prevents it from sticking to the pan. A frequent misstep is increasing heat too quickly, which can cause a stubborn caramelization on the bottom; keep it steady at medium and keep stirring so nothing clings.
Once at a full boil, continue boiling for 5 minutes, stirring continuously.: You'll know it's a full boil when the surface becomes tumultuous and the steam rises steadily, not just a few bubbles. That five minutes is crucial for developing the sugar concentration for a proper set and the right fudgy texture. Keep stirring to avoid burning, and watch the aroma deepen to a slightly toasty, caramel like smell. If you stop stirring, the mixture can scorch at the bottom, leaving a burnt flavor that ruins the batch.
Remove from heat and stir in instant coffee.: The pan will settle into a calmer simmer when removed, and adding the instant coffee off the heat ensures it dissolves without extra bitterness from prolonged boiling. Swirl gently and notice the fragrant coffee lifting the chocolate notes. A common error is adding coffee to boiling liquid, which can amplify bitterness, so let the heat release before stirring it in.
Stir in chocolate chips. (I use a whisk to get out all the lumps.): As the dark chocolate chips meet the hot mixture you will see them soften and then melt into glossy ribbons, a visual cue that the emulsion is forming. Using a whisk can help smooth small pockets, creating a silky texture. If chips are added to a cooled mixture, they will take longer to melt and can create lumps, so add them while the mixture is still quite hot.
Stir in marshmallow creme and vanilla extract.: When you fold in marshmallow creme the mixture lightens slightly and becomes attractively glossy, and the vanilla extract brightens the overall aroma. Stir until the texture looks uniform and slightly billowy. Overmixing can incorporate too much air, which affects density and can make slices crumbly, so fold with intention rather than beating aggressively.
Pour into prepared baking dish.: Pouring produces a satisfying, smooth ribbon as the fudge settles into the parchment. The surface should look thick and uniform; if it seems too thin, it may not set as firmly. Work carefully to avoid splashing on the edges where it might burn during setting. If you notice uneven thickness, tap the pan gently on the counter to level the mixture before it sets.
Sprinkle on peppermint crunch baking chips and let sit for five minutes. Use an offset spatula to gently spread softened peppermint chips.: The warmth of the surface will slightly soften the Andes peppermint crunch baking chips , allowing them to adhere without fully melting. After about five minutes the chips will be pliable, and using an offset spatula you can coax them into an even layer, creating a pretty top. A mistake is waiting too long, then the chips will harden and crack when you try to smooth them; act while they are still tacky.
Sprinkle with crushed candy canes and let cool completely.: The crushed candy canes scatter a bright crunch across the top and create a festive look, and as the fudge cools the mint will set into place. You should feel the surface transition from warm and slightly soft to room temperature and firm. Rushing this by refrigerating too quickly can create condensation that dulls the finish, so allow it to cool at room temperature first, then chill if needed.
Cut into squares and serve.: When you cut the fudge, use the lifted parchment to remove the slab from the pan and a sharp knife for clean edges; you may warm the knife slightly to get smooth cuts. The knife should glide through with minimal crumbling and you will hear a soft snap from the peppermint pieces. Cutting too soon will produce squashed edges, so ensure it is completely set before slicing.
