Combine 2 cups boiling water and porcini mushrooms in a bowl. Cover and let stand 30 minutes or until tender. Strain through a fine sieve over a bowl; reserve 1 1/2 cups liquid and mushrooms.
Cut off pointed end of garlic just to expose cloves; set aside.
Heat a Dutch oven over medium-high heat. Add oil to pan; swirl to coat. Add onion and leek; sauté 5 minutes or until tender, stirring occasionally. Add porcini mushrooms, garlic, cremini mushrooms, and next 4 ingredients (through bay leaf); sauté 10 minutes or until cremini mushrooms are tender, stirring occasionally. Add wine; cook until liquid evaporates (about 2 minutes).
Add reserved 1 1/2 cups mushroom liquid and 6 1/2 cups water; bring to a boil. Reduce heat, and simmer 50 minutes.
Strain through fine sieve over a bowl; discard solids. Store in an airtight container in the refrigerator up to 1 week