• Prepare a greased 9x13 baking dish lined with wax or parchment paper. It's also very helpful to have a strong silicone spatula or a large metal spoon. These rice krispie treats are very thick and sticky as they come together.

Melt the marshmallows

• We'll start by melting the butter over medium-low in a large, deep, nonstick pan or pot.
• Add 10 oz of marshmallows in with the butter. Stir continuously with a spatula until they are fully melted; this can take several minutes.
• Add in the vanilla extract and stir to incorporate. Then add in the 1/2 cup of chocolate chips and mix until they melt.

Mix in the cereal

• Turn off the heat and add in the cereal, mixing it evenly into the gooey marshmallow mixture. Yes, it's very thick and sticky; that is normal. As you are mixing, add in a few handfuls of mini marshmallows, they will partially melt creating marshmallow swirls.

Transfer to a pan & add toppings

• Transfer the mixture to the prepared pan.
• I like to use food-safe gloves or clean, buttered hands work as well to gently press the mixture evenly down into the pan. Don't press too hard; otherwise, the rice krispie treats will become too thin and compact.
• Immediately top them with extra marshmallows, sprinkles, and mini chocolate chips while the mixture is still tacky. Gently press them down so they stick to the mixture as it dries. Allow it to set for 2 hours before slicing into squares.