Quarter the leek lengthwise and slice crosswise into 1/4-inch-thick pieces. Place leeks in a large bowl of cold water and let stand for 5 to 10 minutes to rid them of dirt and sand. Lift leeks out of water with slotted spoon and drain.
In a medium skillet, heat 1 tablespoon olive oil over low heat; add the garlic, shallots, leeks, and salt and pepper. Cook until very soft but not browned, about 15 minutes. Add the peas raising the heat to medium, and cook stirring, until peas are heated through, 3 to 5 minutes.
Transfer the pea mixture to a food processor. Add chicken stock and remaining tablespoon of olive oil; pulse until mixture is a coarse puree, about 12 pulses. Transfer half the puree to a medium bowl. Process the remaining half of the peas for 15 seconds, then combine with the coarsely pureed peas. Adjust seasoning with salt and pepper, if necessary.
Cut bread into 1/4-inch slices, brush with oil, and toast under the broiler on both sides until golden brown. Spread with the pea mixture, garnish with mint and serve immediately or at room temperature.
(c)2004 Martha Stewart Living Omnimedia, Inc. All Rights Reserved.