Line a 8x8-inch baking pan with parchment paper or wax paper. * Tip - Spray the pan first with cooking spray and then line it. The spray helps the paper adhere to the pan and keeps it in place. In a microwave-safe bowl, or in a large pot over low heat on the stove top, melt the butter. Once melted, add in the mini marshmallows and heat in 30 second increments (if using microwave), stirring after each one, until the marshmallows are completely smooth and melted.
4 tablespoons butter, 1 bag (12 oz) mini marshmallows
Stir in the vanilla extract (if using the stove top, remove the pot from the heat before stirring in the vanilla).
½ teaspoon vanilla extract
Add in the rice cereal and stir until well combined and all the cereal is coated in the marshmallows.
6 cups Rice Krispie cereal
Pour half of the Rice Krispie mix into the prepared pan. Use wax paper, or spray your hands with cooking spray, to gently press the mixture into the dish. About 1/2-inch to 1 inch thick and the top should be smooth and flat.
Use the remaining Rice Krispie mix and spoon 3-4 tablespoons over the 8 fruit roll-ups. Place 6 mini Swedish Fish on top of the Rice Krispie treats. Roll it up tightly. Cut each 'sushi roll' into 4 pieces.
Next, cut the pan of Rice Krispies into 1x2-inch rectangles. Place a large Swedish Fish candy on top. Use the remaining two fruit roll-ups and cut them in 1-inch wide strips to wrap around each sushi piece. * The pan should yield 18 small rectangle pieces. These candy sushi rolls are best enjoyed immediately.