Spray an 8×8-inch baking dish with nonstick cooking spray and set it aside.

In a large pot over medium heat, melt the unsalted butter. Stir in the sweetened condensed milk and molasses until combined.

Add the miniature marshmallows to the pot, stirring frequently until they’re fully melted and smooth.

Remove the pot from heat and stir in the ground cinnamon, ground ginger, ground cloves, ground nutmeg, and kosher salt.

Using a rubber spatula, gently fold in the crispy rice cereal until evenly coated.

Transfer the mixture into the prepared baking dish, pressing it into an even layer.

Let the bars cool completely at room temperature before cutting them into squares.