Preheat oven to 400 degrees.
In a large stockpot, melt butter over medium heat. Add onions and garlic and cook until soft.
Reduce the heat to medium-low, and add spinach by handfuls, stirring constantly, until the spinach wilts. Continue cooking, stirring often, until most of the water from the spinach is cooked off. Remove from heat and strain; put back in pan. Stir in oregano and season to taste with Tabasco, salt and pepper. Set aside to cool.
Roll out 1 sheet of thawed puff pastry to around a 14-inch square – it should be large enough to cover the bottom and up the sides (close to the top) of a 10-inch springform pan. Transfer to pan, and gently push on bottom and sides of pastry to remove any air from underneath. Set aside.
In the pastry shell, evenly layer (in the following order) half of: the ham, basil leaves, Provolone cheese, red peppers, spinach mixture, and eggs. Repeat layers. Fold the excess pastry from the sides of the pan over the filling. Brush top of folded over pastry with egg white.
Roll out second sheet of puff pastry to slightly larger than a 10-inch square. Lay over the top of the pan; cut off any excess around the sides so that the second sheet fits snugly in the pan, on top of the torte. Gently press down around the edge to adhere. Put a few cuts in the top pastry sheet, to allow steam to escape. Brush top with egg white.
Place pan on a rimmed cookie sheet and bake on middle rack in preheated oven for 35 minutes. Reduce oven temperature to 350 degrees and continue baking for an additional 45 to 50 minutes. Pastry should be slightly puffed and golden brown.
Cool at least 10 minutes before cutting into wedges and serving. I like this torte best when warm but it is also good served at room temperature. I don’t recommend serving it cold.