Preheat the oven to 400 degrees F.
On a lightly floured surface, roll out the pie dough to an 11-inch circle. Transfer to a 10-inch tart pan with a removable bottom and press the dough against the sides. Refrigerate for 20 to 30 minutes. Line the shell with parchment paper and fill with pie weights. Bake for 10 minutes. Remove the paper and weights, and bake until golden brown, 10 to 15 minutes. Remove from the oven and cool on a wire rack before filling.
Reduce the oven temperature to 325 degrees F.
To prepare the filling, whisk the buttermilk, sugar, eggs, Meyer lemon juice, flour, lemon peel in a medium bowl. Pour into the cooled crust and bake until the filling is set, 25 to 30 minutes. Cool completely then cover and refrigerate until well chilled, at least 3 hours.
Add cream to the bowl of an electric mixer and beat to soft peaks. Add confectioners' sugar and beat to stiff peaks.
To serve, slice tart and place on dessert plates. Place a dollop of sweetened whipped cream on the side and garnish with powdered sugar and lemon slices.
Yield: 1 tart, about 8 servings