Heat oven to 350.
Saute bacon until crisp. Drain all but ¼ of bacon drippings.
While the bacon is cooking, place thawed puff pastry sheet in pie pan and crimp edges. Refrigerate until ready to fill.
Add butter to the pan with crisped bacon and ¼ cup drippings.
Once the butter has melted, set aside.
Add onions to the pan with bacon and caramelize, being careful not to burn the bacon.
Add potatoes, dill and salt & pepper. Stir until well combined.
Add the potato and bacon mixture to the pie pan.
Pour half & half over the filling, doing your best to distribute it throughout the filling.
Bake 50 minutes until tender and golden. Make sure the bottom of the pie is cooked through. It won't hurt to leave it in a little longer!
Let the pie set for 10 minutes.
Sprinkle with cut chives and serve.