What size round is used in the photo associated with this recipe? I have many sized pans and prefer to make round rather than 9 x 13.

The area of a 13 x 9” pan is 117 square inches. If you divide 117 by 3.14 (~pi), you get 37. The square root of 37 is ~6, so you’d need approximately a 12 inch round pan to have about the same area as the 9 x 13 pan. That said, what isn’t accounted for here is volume, or the depth of the pan. Maybe you have a 12” round pan. I don’t, but I do have a 9” deep dish pan. So I’d probably use that and figure I might have some leftover pastry and filling, which I’d bake in a ramekin for a snack or breakfast.