Wash the zucchini and trim off and discard both ends. Using a mandolin or a sharp knife, cut each zucchini lengthwise into long julienne strips 1/8-inch thick, stopping when you reach the cottony center of the zucchini. Rotate the zucchini and continue cutting until all the firm flesh has been removed. Discard the centers and set aside the julienne strips. (You should have about 6 cups.) Heat the butter and oil in a large skillet. When they are hot, add the shallots and saute' for 15 seconds over medium to high heat. Add the zucchini, salt, and pepper, and saute' over high heat for 4 minutes. Serve immediately. Nutritional analysis per serving: calories 116; protein 2 gm; carbohydrates 7 gm; fat 9.9 gm; saturated fat 2.7 gm; cholesterol 8 mg; sodium 142 mg.