1eggyolk mixed with a tablespoonful of water to use as egg wash
1tbspnall-purpose-flour for sprinkling on the rolling surface
Dressing for Salad
3tbspnsherry or white wine vinegar
1/4 cuplightly toasted sliced walnuts or almonds
Mix salad dressing ingredients and set aside until ready to use
Gather all ingredients before starting recipe
Pre heat oven to 400°
Place puff pastry in fridge over night or let sit for an hour at room temperature before starting. Note that the puff pastry must be cool, if defrosting on the counter, check periodically to make sure that it does not become too soft; if it does, place in fridge for 10-15 minutes before using,
Sprinkle rolling surface with flour and roll pastry to one inch larger than the sheet, or, to a 9 x 12 inch rectangle. Lay the rolled pastry on a cookie sheet lined with parchment paper.
Spread a thin layer of Dijon mustard on the bottom sheet of puff pastry
Lay sliced ham folded in half and overlapping on the mustard. Leave a 1/2" border on all sides of the pastry.
Add a couple of handfuls of fresh spinach leaves over ham and sprinkle with grated gruyere cheese
Roll out the second sheet of puff pastry to be slightly smaller than the bottom sheet and place this over the ham/cheese mixture. Turn up the edges of the bottom sheet over the top sheet and pinch to make a nice border all around.
Cut 3 slits in the top of the pastry and using a pastry brush, brush the top of the pastry with the egg wash. If not baking right away, place the tarte in the fridge until ready to bake.
Bake for 30-40 minutes in a non-convection oven, or until the top is nicely browned.
Allow the tarte to cool slightly, then slice into serving portions.