Chicken and Artichoke-Heart Potpie

INGREDIENTS

• 3 whole chicken breasts (about 1 1/2 pounds each), bone in, skin on
• 3 tablespoons olive oil
• 2 1/2 teaspoons salt, plus more for sprinkling
• 1 teaspoon freshly ground pepper, plus more for sprinkling
• 1 quart homemade or canned chicken stock
• 2 chicken bouillon cubes
• 1/2 pound (2 sticks) unsalted butter
• 2 1/2 cups coarsely chopped yellow onion (2 medium onions)
• 1 cup all-purpose flour, plus more for work surface
• 1/4 cup heavy cream
• 2 nine-ounce packages frozen artichoke hearts, thawed and halved lengthwise
• 1 1/2 cups (about 7 ounces) frozen peas
• 1 1/2 cups (about 8 ounces) frozen small, whole onions
• 1/2 cup minced fresh flat-leaf parsley
• 1/2 cup grated Parmesan cheese
• Pie Crust
• 1 large egg mixed with 1 tablespoon water for egg wash