Line a 9x13 cake pan with tin foil. Spray the tin foil with nonstick cooking spray.
In a large saucepan, add in the butter over low heat. Let it melt.
Add in the bag of marshmallows and stir constantly until the marshmallows are melted and smooth. Remove from heat.
Add in the rice krispies cereal and stir until the gooey marshmallow has coated all of the cereal.
Dump the rice krispies cereal into the prepared pan.
Spray a piece of wax paper with nonstick cooking spray and press it against the rice krispies until a firmly packed bar forms. Be sure to get the corners filled in too. Let the bars cool completely.
Cut the bars in half the long way and and then into 8 large bars.
Add the chocolate almond bark into a microwave-safe bowl and microwave for 30 second intervals and stir after each time until the almond bark is smooth.
Lay wax paper out on the counter to lay the bars to dry after they're dipped in the chocolate and sprinkles.
Dip the end of the rice krispie treats into the almond bark. Pick it up and let any excess almond bark dip off.
Dump the sprinkles on a plate with a little lip to catch any sprinkles near the edge.
Dip the end of the rice krispie treat into the sprinkles. Lay the bar on the wax paper to dry. Repeat with the rest of the rice krispie treats.