Zucchini Boat Gratin

4        zucchinis4        tablespoons olive oil1        medium onion, finely chopped8        ounces soy vegetable protein crumbles, or chopped mushrooms1        clove garlic, mashed1        fresh fennel julienned4       cups skim milk3        tablespoons cornstarch1        tablespoon chopped fresh tarragon1/8   teaspoon fresh nutmeg1/8   teaspoon allspicesalt and pepper to taste-To make the boats; In  a deep pot, bring salted water to a boil.  Cut the zucchini lengthwise in half and drop the zucchini in the boiling water.   Bring back to a boil and  boil for couple of minutes.  Drain and allow the zucchini to cool.  Scoop out the inside of the zucchini with a teaspoon.  Place the zucchini halves, cut side up, in a baking pan.-To make the stuffing; Heat the olive oil and cook the onion for couple of minutes.  Add the soy protein, the garlic, little salt and pepper.  Stir and cook over low heat for 5 minutes.-To make the sauce; Mix the cornstarch with 1 cup of milk.  Mix well until the cornstarch dissolve.   Mix with the rest of  the milk and pour into heavy sauce pot and add the nutmeg, the tarragon and salt, stir and place over medium heat.  Cook , stirring constantly until the sauce thicken slightly and coat the back of the stirring spoon.  Remove from the stove, add the fresh fennel and set aside.-To asseble the dish; divide the stuffing between the zucchini halves.  Pour the sauce over the stuffed zucchini.  Bake in a 375 F degree oven bake for 30 minutes.  Serve with rice.-