Beat the eggs and both sugars together in a mixing bowl until light and fluffy. Stir in the pumpkin purée, spices, and salt and mix thoroughly. Stir in the cream and half-and-half.
Roll out the pastry on a lightly floured work surface and line a 9-inch pie pan with it; trim and crimp the edges. Pour in the filling.
Bake the pie for 8 minutes, then reduce the heat to 325°F and bake until the filling is set (a knife inserted in the center will come out clean), another 40 to 45 minutes.
Arrange the pecan halves decoratively around the edge, pressing them lightly into the warm filling. Arrange another 5 pecans in a flower pattern in the center of the pie. Cool completely before cutting.