Combine the flours and salt in a bowl. Make a well in the center and add the cold lard and oil. Working with your fingertips or a pastry cutter, blend the fat and flour until the mixture resembles coarse crumbs.
Sprinkle with 7 tablespoons of the water, and toss with a fork until the dough begins to form clumps. If it is dry, add more water. Gather the bits of dough into a ball, wrap, and chill at least 30 minutes. When ready to assemble, halve dough and roll into 2 rounds a little larger than a pizza pan. Fit 1 round into the pizza pan.
Heat the pancetta with the oil in a large skillet over medium-low heat. Cook about 5 minutes, or until the pancetta has given off much of its fat.
Add the onion and garlic and cook, covered, 15 minutes or until softened. Uncover, raise the heat to high, and cook another 6 minutes, or until a rich golden brown.
Add the spinach or chard, and saute 3 to 5 minutes, adjusting the heat to prevent burning.
If a brown glaze forms on the skillet bottom, add a little water and simmer, scraping it up with the spatula to incorporate the glaze with the filling. Cook a minute or so until the liquid evaporates. Turn the filling into a bowl and cool. Blend in 1 1/2 cups of the cheese and reserved pancetta mixture. Taste for seasoning and for enough cheese, and then blend in the eggs.
Preheat the oven to about 400 degrees F. Set the rack as close to the bottom of the oven as possible.
Combine the lard and garlic in a small pan and heat over medium heat 2 minutes, or until the lard has melted.
Spread the filling over the pastry-lined pizza pan, leaving about a 2-inch border. Dampen the edges with water, top with the remaining dough, and pinch the edges together. Fold the edges over toward the center of the tart, and crimp. Make slashes in the top of the crust.
Bake 20 minutes, then brush the crust with the melted lard and garlic mixture, and bake another 20 minutes, or until pale gold and very crisp. The edges of the tart will be golden brown.
