Grease a 9x13-inch baking pan or line it with parchment paper for easy removal later.
In a medium saucepan over low heat, combine the unsweetened peanut butter, maple syrup or honey, and ½ cup of unsalted butter or coconut oil. Stir continuously until melted and well combined. Remove from heat and stir in the optional vanilla extract.
In a large mixing bowl, add the crispy rice cereal. Pour the melted peanut butter mixture over the cereal and gently fold until the cereal is completely coated.
Transfer the mixture into the prepared baking pan. Using a rubber spatula, press the mixture down firmly and evenly into the pan.
In a double boiler or microwave-safe bowl, combine the chocolate chips, butterscotch chips, and the remaining 2 tablespoons of unsalted butter. Melt until smooth, stirring often. If using a microwave, heat in 30-second intervals to prevent burning.
Pour the chocolate-butterscotch mixture over the pressed cereal layer in the baking pan. Use a spatula to spread it evenly over the top.
Refrigerate the pan for at least 1-2 hours, or until the bars are firm to help them hold their shape when cut.
Remove the bars from the pan using the parchment paper if used. Cut into squares or rectangles, and enjoy!