french onion tart + uk cookbook release

INGREDIENTS

• 2 cups (250 grams) all-purpose flour
• 1/4 teaspoon table salt
• 1/2 cup (1 stick, 4 ounces or 113 grams) chilled butter, in cubes
• 3 tablespoons cold water
• 1 1/2 pounds yellow onions (about 4 medium), halved and thinly sliced
• 1 tablespoons butter
• 1 tablespoon olive oil
• Scant 1/2 teaspoon table salt
• Pinch of sugar
• 1 cup low-sodium beef, veal or mushroom stock/broth
• 2 teaspoons cognac, brandy or vermouth (optional)
• Freshly ground black pepper
• 1/2 cup (about 2 ounces or 60 grams) grated Gruyere, Comte or Swiss cheese
• 1 large egg
• 1/2 cup heavy cream (half-and-half and milk work too, but cream tastes best)