CRUST: Beat butter and sugar until smooth. Add cornmeal, eggs and salt and beat until well combined. Add flour and mix until dough forms a ball. Mixture should be soft and moist. Wrap in plastic and chill for 1 hour. Roll out the crust to fit a prepared 9x1 inch tart pan with removable bottom. Wrap and save any leftover dough in freezer. Prick with a fork several times and bake for at least 8 minutes at 350 degrees until lightly browned.
RICOTTA CHEESE-LEMON THYME FILLING: Saute shallots in butter until soft, not brown. Add cream, wine, salt and white pepper. Reduce by one half. Cool. Add ricotta cheese, eggs and thyme and beat until smooth. Pour into prepared tart shell. Bake in a 350 degree preheated oven for 35-40 minutes, or until the filling is just set and lightly browned.
Serve warm or at room temperature. Garnish with a sprinkling of herbs.