Last week, in our campaign to Save the Leftover Bread, we covered how to make homemade breadcrumbs and gave you two reasons why: spaghetti with crispy crumbs and brown bread ice cream. Here's another reason to always save your sad, stale little baguette heel and turn it into crumbs: Rouille.

The Provencal condiment is essentially a mayonnaise (egg yolk emulsified with oil) but with the addition of breadcrumbs and chili. While it's good in all the same places as regular mayonnaise: sandwiches, roast chicken etc., rouille's classic companion is fish. And the most delicious fish (not to mention the cheapest, and most sustainable) are the little oily guys.

Seriously, fresh sardines don't need much help being tasty (just a little salt, pepper, good olive oil, and a squeeze of lemon once they're cooked). Buy the sardines the day you plan on eating them. If you don't like them looking at you with their googly eyes, you can filet them, or ask the fishmonger to do it for you (the very thin flexible bones are edible). But frying them head on is easy, and makes for a rustic presentation. Nothing wrong with that. You can make the rouille in advance and keep it in the fridge (but not for longer than a day or two) and serve with some raw sliced radishes or a simple green salad.

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