Heat oven to 400 F.

In large skillet, add water and asparagus. Cook 5-8 minutes until asparagus is bright green.

Drain asparagus and soak in ice water.

In large bowl, mix drained asparagus, vegetable oil, salt and pepper until combined.

Flour surface area. Using rolling pin, roll out pastry to 10-by-16-inch rectangle. Transfer pastry to parchment-lined baking sheet. Prick pastry with fork. Bake about 12 minutes, or until golden brown. Cool slightly on baking sheet.

In large bowl, mix fontina cheese, gruyere cheese, shallot, egg yolks, milk, nutmeg and salt and pepper, to taste, until combined. Spread cheese over pastry, leaving 1 inch around edges. Lay asparagus over cheese mixture.

Bake 5 minutes, or until cheese has melted.

Sprinkle lemon zest over tart and serve.