Line an 8x8 pan with parchment paper and set it aside.

In a large mixing bowl, combine the crispy rice cereal, chopped pretzels, chocolate chips, and an extra handful of unmelted mini marshmallows if desired.

Melt the butter in a large saucepan over medium-low heat until completely liquid. Add the peanut butter to the saucepan and stir until fully melted and combined with the butter. Add the 10 ounces of mini marshmallows and stir continuously over medium-low heat until completely melted, smooth, and fluffy. Remove the saucepan from the heat, add the vanilla bean paste, and mix thoroughly.

Pour the warm peanut butter marshmallow mixture over the cereal, chocolate, and pretzels. Working quickly before the mixture sets, use a greased spatula to fold everything together until evenly coated.

Transfer the mixture into your prepared 8x8 pan and press down lightly with a spatula into an even layer without packing it down too firmly.

Place the 16 whole pretzels on top of the chocolate drizzle so each sliced treat gets one pretzel. Sprinkle flaky sea salt across the top to finish.

Let the treats cool and set at room temperature for at least 1 to 2 hours before slicing into 16 squares and serving.