A question about a recipe: Individual Sweet Potato Gratins with Creme Fraiche, Onions, and Bacon

I have a question about step 1 on the recipe "Individual Sweet Potato Gratins with Creme Fraiche, Onions, and Bacon" from apartmentcooker. It says: What sized baking dish would you recommend if I didn't use individual ones? I want to make one big dish.

"Lightly grease 2 individual baking dishes (I used a bowl that holds roughly 1 1/2 cups). Preheat the oven to 350 degrees."