Asparagus, Ham and Gruyere Tart | The Kitchen Scout

Ingredients

• 3 Tablespoons unsalted butter
• 1 large sweet onion such as Vidalia, sliced thinly into half moons
• Kosher salt and freshly ground black pepper
• 1 sheet frozen puff pastry, thawed but still cold
• 4 slices baked Virginia ham
• 12 Asparagus spears, ends trimmed
• 1 1/2 cups freshly grated Gruyere or Aged Provolone Cheese, about 4 ounces
• 2 teaspoons extra virgin olive oil
• 1 teaspoon chopped fresh garlic
• 1 Tablespoon freshly grated Parmesan Cheese, more for finishing
• 1 egg, beaten
• 1 scallion, thinly sliced or 1 Tablespoon chopped fresh chives for garnish