Make pie dough and refrigerate for at least 30 minutes (or make a day ahead of time).
Preheat oven to 400 in preparation to partially bake your pie crust.
Line plated pie crust with foil so that it covers the entire crust, including the edges. Fill to the top with pie weights or dry beans/rice. Make sure that the weights go up the sides to prevent shrinking.
Bake for about 20 minutes.
Gently remove foil and weights, pierce with a fork if the crust puffs at all, and put back in the oven for about 10 minutes or until just beginning to brown. Remove from oven and let cool while you prepare your filling.
Peel and slice pears not thicker than 1/4 inch – the thinner the better. Toss together with lemon juice and ginger in a medium bowl. Arrange the pears in rows or any other decorative way, standing on edge along the bottom of the crust.
Whisk the sugar and eggs together until well blended. Add in the cream. Continuing to whisk well, add the vanilla, nutmeg, cinnamon and rum. Pour mixture over pears into the pie shell.
Place pie on the center rack of the oven and cook at 350 for 35-40 minutes until the middle is JUST set. It will still jiggle just a tad. Cool completely before slicing.
*About 8-10 minutes into the baking, place cranberries (if using) in middle for decoration. They tend to float away, so I wait until the pie has started to set a bit.