My Grandma always made this in addition to any other pie she was baking. After she passed away in 1984, the recipe was no where to be found. She must have had it memorized! After several years of baking every recipe I could find, I decided to develop my own. This is good warm or at room temp, but if you can wait, it is better the next day after spending the night in the refrigerator! I taught cooking classes for several years and this was a favorite with my students.
Line a 9" pie plate with pastry. Trim and flute edges, set aside.
In a large bowl, combine flour, sugar and salt. In a large mixing bowl beat together the buttermilk, eggs, melted butter, lemon juice, lemon peel and vanilla. Add to the dry ingredients, mix well. Pour into pie shell and sprinkle with nutmeg.
Bake at 400 degrees for 10 minutes. Reduce heat to 325 degrees, bake 40-45 minutes longer or until a knife inserted in the center comes out clean. Cool on a wire rack. Serve at room temperature or chilled. Store in refrigerator.