Prepare the muffin tins. Preheat your oven to 400°F. Spray two muffin tins with nonstick cooking spray. If you only have one muffin tin, you can make the candy in two batches.

Add the crackers. Place one Ritz cracker into each muffin cup.

Make the toffee. Add the butter and brown sugar to a saucepan. Heat until the mixture boils, then continue boiling for 2–3 minutes, until it reaches 300°F on a candy thermometer.

Add the toffee mixture. Carefully spoon about 1 tablespoon of the hot toffee mixture over each cracker. Divide any extra mixture among the cups.

Bake the crackers. Place the muffin tins in the oven and bake for 4 minutes.

Add the chocolate. Remove the tins from the oven and sprinkle the chopped chocolate over the hot toffee. Let it sit for 4–5 minutes to melt, then spread the chocolate evenly over each candy bite.

Decorate the candies. Add toffee pieces, Christmas sprinkles, M&Ms, or your favorite toppings while the chocolate is still soft.

Cool and chill. Let the candies cool, then refrigerate for about 1–2 hours until firm.

Remove from the muffin tins. Carefully slide the tip of a small, sharp knife along one side of each candy to loosen it, then gently lift it out.