The recipe calls for 4 small onions and 1 large leek, but you may use any combination of vegetables you like, more leeks and fewer onions, or more onions and fewer leeks. If your onions are very large, you may use 2 or 3 onions. The point is you want a heaping pan of uncooked veggies. (See the picture just below.)
Find it online: https://www.weaversorchard.com/expand-your-palate/