Preheat your oven to 375°F and prepare a 9x13-inch baking dish with cooking spray or butter. Peel and cube the sweet potatoes into 1-inch pieces for even cooking throughout. Bring a large pot of salted water to a boil and add the sweet potatoes.

Boil the potatoes for 12-15 minutes until fork-tender, then drain thoroughly in a colander. Transfer to a large mixing bowl while still warm so they absorb the spices and seasonings better. This timing ensures the potatoes mash smoothly without becoming gluey.

Add butter, brown sugar, cinnamon, nutmeg, salt, orange juice, vanilla extract, ginger, and heavy cream to the warm potatoes. Mash until you reach a smooth consistency with small lumps remaining for texture interest. Stir in the eggs and cornstarch until fully incorporated, creating the base for your summer sweet potato casserole crowd recipe.

Fold in the chopped pecans gently to distribute them evenly throughout the filling. Pour the mixture into your prepared baking dish, spreading it level with a spatula. Drizzle the maple syrup across the top in a thin pattern for extra sweetness in every bite.

Bake at 375°F for 35 minutes until the edges begin to bubble and the center is set. Remove from oven and distribute marshmallows evenly across the surface, pressing slightly so they stay put during final baking. Return to oven for 12-15 minutes until marshmallows are golden brown and slightly melted into the filling.

Let the casserole cool for 10 minutes before serving so the structure sets and marshmallows firm up slightly. The sweet potato casserole will continue firming as it cools, making serving cleaner and presentation prettier.