Line or spray a 9x13 baking pan. Set aside. Pour the rice krispies into a large heat proof bowl, set aside.
Prep your smarties by finding pairs of colours. Then with a sharp knife, cut one of the pairs in half. So you'll have one whole smartie and 2 halves to form each bunny. Repeat this with all of the smarties and set aside. I keep them all together on the cutting board so the pieces stay together.
In a large pot, add the sugar, corn syrup and peanut butter. Heat over a medium low heat while stirring every 30 seconds or so. Heat until the mixture comes to a gentle boil. Remove from heat and stir in the lemon zest. You can just zest the lemon right into the pot. Pour the mixture over the rice krispies.
Using a spatula or wooden spoon, stir the peanut butter mixture gently into the rice krispies until combined. Then pour the rice krispies into the 9x13 pan.
Press the mixture down gently so it's flat and even in the pan. DON'T press down too hard or you'll make the scotcheroos tough and hard to bite.
In a heatproof bowl, add the chocolate chips and butterscotch chips. Heat in the microwave in 30 second increments, stirring in between, until melted. Pour over the rice krispies and use a spoon or spatula to spread evenly around. Give the pan a little shake after to make the chocolate go completely flat.
Make your bunnies on top by placing 1 whole smartie flat. Then take the matching one that you cut in half and line them up vertically, cut side down, with the full smartie to form the bunnies ears. Repeat this until you've used all your smarties. You can lay them out in a random way like I did or you can put them so each square you plan to cut has a bunny.
Allow everything to fully cool for a few hours or pop them in the fridge for 30 minutes. Cut into squares and enjoy!