Preheat oven to 350 degrees F (175 degrees C).
Unroll pie crust. Cover the bottom a 9.5-inch pie plate or deep dish pie pan.
Trim edge, leaving a 1/2-inch overhang. Fold overhang under and lightly press against rim of pie plate, then crimp decoratively.
In a medium bowl whisk together butter and sugar until light.
Then add eggs, vanilla and continue mixing.
Stir in flour,, lemon zest ,nutmeg and salt and continue beating until smooth . Then add buttermilk, followed by pineapple , if desired.
Pour mixture into a prepared pie pan and bake at 400F for 10 minutes, reduce heat to 350F and bake for 50-60 additional minutes.
Pie should turn a nice golden brown and a tooth peak inserted should come out clean.
Let it cool for at least an hour or more before serving. If adding pineapple you might have to cool longer.
Serve at room temperature with whipped creamed.