Mushroom Pie
["3 c. flour", "1 egg yolk (save white for later)", "1/2 tsp. salt", "1 c. margarine", "3 to 4 Tbsp. ??? or more if dry"]
["Refrigerate in wax paper for 10 minutes.", "Makes 2 crusts."]
["flour", "egg yolk", "salt", "margarine"]