Preheat oven 350. In large bowl, add the melted butter to the beaten eggs, whisk slightly. Add buttermilk, blend slightly. Combine sugar and flour whisk. Add to the wet ingredients. Add vanilla, lemon juice and nutmeg. Blend slightly.
Pour into unbaked deep dish pie crust. Bake at 350 degrees for 55-60 minutes or until brown on top. Remove from oven, place on bakeing rack and cool throughlly before serving.