Image of Red Onion Tart

Red Onion Tart

Prep Time: 25 min
Cook Time: 35 min

Ingredients

  • 1 (.25 ounce) package active dry yeast
  • 1 pinch white sugar
  • ½ cup warm water
  • 1 egg, at room temperature
  • 3 tablespoons butter, at room temperature
  • 2 ½ cups all-purpose flour
  • 1 teaspoon salt
  • 2 teaspoons lemon zest
  • ½ teaspoon vegetable oil
  • ½ red onion, sliced
  • 1 cup shredded Gouda cheese
  • ½ cup grated Parmesan cheese
  • 2 jarred roasted piquillo peppers, diced
  • ¼ teaspoon ground black pepper to taste
  • 2 eggs
  • 1 ½ cups heavy cream
  • ¼ teaspoon stone-ground mustard