Grease a 9 x 13-inch pan with softened butter.

In a large non-stick saucepan, melt the butter over medium heat, stirring constantly until it turns slightly golden and has little brown flecks throughout.

Add the marshmallows and stir until completely melted. Remove from heat.

Stir in the vanilla bean paste and salt until well combined.

Add the Rice Krispies cereal and stir until well coated.

Using a buttered spatula or wax paper, evenly press the mixture into the greased 9 x 13-inch pan. Sprinkle with Maldon salt if desired.

Let cool, then cut into 2-inch squares using a knife sprayed with cooking spray or coated with softened butter.

Enjoy immediately or wrap each square tightly with cling wrap for later.