1. Grease or line a 9×13-inch baking pan with parchment paper and set aside.
2. In a large pot over medium heat, melt the butter completely. Once melted, add the mini marshmallows and stir constantly until melted and smooth—about 3 to 5 minutes. From experience, keep the heat moderate to avoid scorching. My first try ended in a sticky mess because I rushed this step!
3. Remove the pot from heat and stir in the vanilla extract and caramel sauce until fully combined.
4. Quickly fold in the Rice Krispies cereal (and nuts if using), making sure every piece is coated in that luscious caramel marshmallow mixture.
5. Transfer the mixture to your prepared pan and use a buttered spatula or wax paper to press it evenly and firmly into the pan. Don’t skip this step—pressing firmly helps the treats hold together better.
6. Sprinkle the flaky sea salt evenly over the top while the treats are still warm. This salty contrast is what brings the whole thing to life. I often sneak a little extra sprinkle for myself.
7. Allow the treats to cool completely at room temperature, about 1 hour. Then cut into squares and enjoy.

Quick tip: If you’re short on time, pop the pan in the fridge for 20-30 minutes to speed up setting. I’ve done this more times than I can count during busy school mornings when I’m prepping snacks.