Sauté the bacon until it's crisp.
Pour off all but a couple tablespoons of the fat, then return the pan to a medium burner and add the onion, leek, and shallot, and cook until they're softened, 5 minutes or so, adding two healthy four-finger pinches of salt as you go.
Add the carrots and continue to cook until till they're bright orange and heated through, 3 to 5 minutes or so.
Turn the heat to high, add the peas, then 8 cups of water. Bring to a simmer. Skim the foam, then turn the heat to low, and cook until the peas are softened, about 40-45 minutes.
Buzz the bottom of the pot with a hand blender, just to make it thick and creamy but not so much that you lose all the carrots and peas about ⅓rd of it pureed.
Serve with a lemon wedge.