Prepare the pan by lining a square or rectangular baking pan with parchment paper, allowing some overhang for easy removal.

Melt 3 tablespoons of softened butter and 4 cups of marshmallows in a large pot over low heat, stirring constantly for 5-7 minutes until smooth.

Remove from heat and carefully fold in 6 cups of Rice Krispies, mixing gently for about 2 minutes until evenly coated.

Pour the mixture into the lined pan and press down firmly to create a compact layer about 1-inch thick, allowing it to cool at room temperature.

Chill the pressed layer in the refrigerator for at least 1 hour to firm up for cutting.

Melt 1.5 cups of chocolate with 1 tablespoon of vegetable oil in a microwave-safe bowl, heating in 30-second intervals until glossy.

Cut the chilled rice krispie layer into pencil shapes and dip each into the melted chocolate, allowing excess to drip off.

Let the chocolate-coated treats set at room temperature for about 30 minutes until the chocolate hardens completely.