No campfire required to create this tasty crowd favourite, any place, any time.
Preheat oven to 350°F (180°C). Grease a 10-inch (25 cm) cast iron skillet.
In large bowl, beat butter and sugars until light and fluffy. Beat in eggs and vanilla.
Add dry ingredients and stir until blended. Stir in 1 cup (250 mL) of the chocolate chips.
Spread dough evenly into prepared skillet. Sprinkle with marshmallows and remaining chocolate chips. Bake for 35-40 minutes or until marshmallows are gooey and cookie is golden brown. Let cool on rack for at least 10 minutes before serving.
To make on BBQ, preheat BBQ to 400°F (200°C). Turn off one burner and place cast iron skillet on that side. Close lid. Bake 45-50 minutes, or until marshmallows and edges are golden – cookie will be soft in the middle. Remove from grill and let stand 10 minutes. Cool and serve.