Chicken and Mushroom Crêpes

1 tablespoon unsalted butter
6 ounces cremini mushrooms, sliced
1/2 cup diced onion
1/3 cup diced celery
1/2 teaspoon finely minced garlic
2 tablespoons butter (not to be confused with the unsalted butter above)
3 tablespoons flour
1/4 cup dry sherry
2 cups homemade chicken stock
2/3 cup heavy cream
Salt and freshly ground black pepper to taste
1 teaspoon chicken soup base (I use Jamison)
2 cups cooked chicken breast, cubed
One package of Melissa's premade crêpes

Preheat oven to 350°. Spray a 1-1/2 quart baking dish with Pam; set aside.

Melt unsalted butter in a 10-inch skillet over medium heat. Stir in mushrooms and cook for 2 to 3 minutes, then stir in onion, cook for 2 to 3 minutes, and, lastly, stir in garlic and cook for one minute more. Add butter, stirring until melted, and then sprinkle in flour, stir together and allow to cook for 1 to 2 minutes to get rid of the floury taste. Stir in the sherry, and the chicken stock, a little bit at a time, continuing to stir in the doing. Bring to a boil, turn down heat, and allow to simmer until mixture begins to thicken, 3 to 5 minutes. Stir in the heavy cream, salt and pepper, and the chicken soup base, and continue to simmer until sauce thickens again. Place chicken in a mixing bowl, and pour some of the sauce on top of it, 1/3 cup at a time, stirring after each addition, until the chicken comes together, much in the same way chicken salad would come together. Divide chicken among six crêpes roll up, and place seam side down into your baking dish. Place into your oven and bake for 25 to 30 minutes. Warm the remainder of the sauce, pour over the crêpes, and serve.