Preheat oven to 425°F.  Lay puff pastry shell flat on a piece of parchment paper or baking sheet.  Using the back of a spoon, spread the mascarpone cheese all over the pastry.  Return pastry shell to the freezer.

Thoroughly wash and dry the blood oranges.  Cut off each end and slice as thin as possible without ripping the flesh of the orange, about ⅛" thick.

In an oven-safe 9" skillet, melt the butter over medium heat.  Add granulated sugar and stir together with a rubber spatula.  Carefully toss the orange slices with the butter sugar mixture.   Once all slices are evenly coated, pat them down in a flat layer with the spatula.  Pour in the rosé wine, reduce the heat to low and simmer for 5 minutes or until most of the liquid has cooked off.

Remove the skillet from heat and top with puff pastry mascarpone side down.  Trim or fold over any edges with a sharp knife or kitchen scissors.

Bake in a 425°F oven for 18-20 minutes until the puff pastry if puffy and golden brown.  Allow to cool for 10-15 minutes before flipping over the tart.  If sugar is too hot, it will run and if the pan is cold the oranges will stick to the pan.

Run a spatula around the edge of the tart. Cover the top of the skillet with a large, flat plate or serving dish and flip skillet over. If it doesn't release immediately, give it a gentle shake. Slice into 6 slices using a pizza cutter or sharp knife.  Serve plain or top with vanilla ice cream.