A question about a recipe: No-Cream Gratin of Potatoes and Carmelized Onions

I have a question about step 3 on the recipe "No-Cream Gratin of Potatoes and Carmelized Onions" from Loulies. It says:

"Peel, and as thinly as possible (a mandoline works well), slice potatoes. Add to the caramelized onions in pan. Season with a pinch of salt and a few grinds of black pepper. Arrange onions and potatoes in medium-sized gratin dish. Cover with foil and bake until potatoes are tender about 35 minutes.



Loulies November 17, 2011
I have a 9 or 10" fluted, white porcelain one that I like to use. Thanks for asking
francesca G. November 17, 2011
I would say about 9 inches in length and 6 inches in width. Approximately! Use whatever you have and if you feel that it is smaller or larger than needed scale down or up the other quantities accordingly.
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