Start by lining a 9×13 inch baking dish with parchment paper for easy removal later, then lightly spray it with non-stick cooking spray to ensure your Ruler Rice Krispies don’t stick. Make sure the parchment hangs over the edges, as this will help you lift the treats out when they are set.

In a large saucepan, melt 3 tablespoons of butter over low heat. Once melted, add the entire 10 oz bag of mini marshmallows and stir consistently for about 5 minutes or until they have completely melted and formed a smooth mixture.

Remove the pan from the heat and quickly add the 6 cups of Rice Krispies cereal. Stir gently but thoroughly until each piece is well-coated with the marshmallow mixture. This should take about 2-3 minutes.

Divide the mixture into three portions in separate bowls. To one bowl, add a few drops of red gel food coloring, mixing until you achieve a vibrant shade. In another bowl, add yellow gel food coloring and mix thoroughly. Leave the last portion plain.

Start pressing the red mixture into the bottom third of your prepared dish, using a spatula to flatten it evenly. Next, layer the yellow mixture in the center third, pressing it down firmly, followed by the plain Rice Krispies mixture on top. Allow the treat to cool completely for about 30 minutes.

Once set, use a sharp knife to cut them into long rectangle bars, mimicking the shape of a ruler.

In two microwave-safe bowls, melt the white candy melts and chocolate chips separately. Heat in 30-second intervals, stirring in between until smooth and silky.

Using a piping bag or a spoon, drizzle the melted chocolate over one edge of the Rice Krispies bars to create the “metal edge.” Then, use the white candy melts to add subtle ruler markings.

Finally, take your black decorating gel or edible marker to carefully draw numbers and small lines along the sides of the bars to complete the ruler effect.

Allow the decorated Ruler Rice Krispies to set for a few more minutes until everything is firm. Then, they are ready to serve!