Spinach TartForm this tart freehand on a baking sheet for a casual, country-style look; for a chic look, use a tart pan.1 (11 ounce) package pie crust mix (for 2 crusts)2 tablespoons snipped fresh herb or 2 teaspoons dried herb    such as tarragon, thyme, basil, oregano, or marjoram10 ounces torn fresh spinach8 ounces reduced-fat cream cheese (Neufchatel), softened1/4 cup light dairy sour cream2 to 4 cloves garlic, minced1/4 teaspoon salt1/4 teaspoon pepper1/2 cup chopped water chestnuts1 beaten egg1 tablespoon waterFresh French wild asparagus or fresh dill weed (optional)Prepare piecrust mix according to package directions, except add 1 tablespoon fresh herb or 1 teaspoon dried herb to dry ingredients. Divide pastry in half. Form each half into a ball.For filling, add spinach to 1-inch of boiling water in a large saucepan; cover and steam for 2 to 4 minutes or just until limp. Drain thoroughly, squeezing out excess water.In a medium mixing bowl stir together cream cheese, sour cream, garlic, salt, pepper, and remaining 1 tablespoon fresh herb or 1 teaspoon dried herb. Stir in the spinach and water chestnuts.For a free-form shape: On a lightly floured surface, flatten each ball of dough with hands. Roll dough from center to edges, forming a circle about 10 inches in diameter. Trim each to a 9 1/2-inch circle, reserving trimmings for pastry cutouts. Transfer one pastry round to a baking sheet; spread spinach filling onto pastry to within 1/2 inch of edge. Moisten edge with water. Top with remaining pastry round; seal and flute edges. Use the back of a knife to make scallops around the edge. Cut slits in top to allow steam to escape. If desired, top with pastry cutouts. To attach, combine beaten egg with water and brush atop crust. Place cutouts atop brushed surface.To prepare in a tart pan: On a lightly floured surface, flatten each ball of dough with hands. Roll dough from center to edges, forming 2 circles about 12 inches in diameter. Transfer 1 circle to an 11-inch tart pan with a removable bottom; spread with spinach filling. Moisten edge with water.Place remaining pastry circle atop filling. Trim edges, reserving trimmings for pastry cutouts. Seal and flute edges. Cut slits in top to allow steam to escape. If desired, top with pastry cutouts. To attach, combine beaten egg with water and brush atop crust. Place cutouts atop brushed surface.Brush any remaining egg mixture onto pastry. Bake in a 425 degree F oven for 20 to 25 minutes or until golden. Serve warm or cover and chill over night. Garnish with fresh French wild asparagus or fresh dill weed, if desired. To serve, cut tart into narrow wedges.Make-ahead directions: To reheat chilled tart, cover loosely with foil. Heat in a 350 degree F oven about 20 minutes or until warm.