Feeling a little thick in the waist and thin in the billfold of late, I've been keeping a closer eye on how much I eat and how much I spend. Soup is my favorite way to address both of these concerns. Last winter I felt frugal and slender buying my daily soup at Le Pain Quotidien, where just under $5 buys you a satisfying portion of bright, delicious vegan soup, a piece of baguette, and a slice of brown bread. It's not a bad deal for lunch in midtown, but it didn't take me long to realize that you can make yourself a week's worth of soup for $5 (thereby avoiding, too, the terrible service at Pain Quotidien, which tries my patience even on the cheeriest days). Making your own leek and potato soup is particularly satisfying--how often do two ingredients plus water and salt end up tasting so good?
I recently pitted Julia Child's potato leek soup (from The Way to Cook) against Deborah Madison's (from Vegetarian Cooking for Everyone). Julia Child's soup is just boiled potatoes and leeks (though she does suggest that you might stir in some cream at service--not for taste, but because cream is "nourishing"--what a woman!). It's better than you'd suppose boiled potatoes and leeks would be, but Deborah Madison's marginally more complicated (though still absurdly simple) recipe is the hands-down winner.
Chop up 1.5 pounds leeks, white part only (perhaps 4 average-size ones? leeks vary so wildly in size that I always weigh). I like to do this by quartering the leek lengthwise without cutting through the root, rinsing the quarters, and then chopping each quarter into half-inch lengths. Slice 1.5 pounds potatoes (I like Yukon Gold best here) into bite-size, fairly thin (1/3 inch) pieces. Melt 2 tbs. butter in your soup pot over medium heat, add vegetables, and cover. Let sit on the heat for 10 minutes, stirring every once in a while. Add water to cover (about 7 cups) and 1.5 tsp salt and bring to a boil. Lower heat, cover partially, and let simmer for about 30 minutes, until some of the potatoes are starting to fall apart. Serve with salt and pepper, and maybe a splash of milk or a spoonful of yogurt.
French Women Don't Get Fat (the production of which, full disclosure, I was involved with at work, though I would honestly, wholeheartedly recommend it even if this were not the case) has some really great, easy, flexible vegetable soup recipes, too...but I wanted to mention the book becauses it was my introduction to leeks, a vegetable whose acquaintance I am very happy to have made.