Onion and Bacon Tart | Saveur

Ingredients

• 6 oz. slab bacon, cut into 1/4″ matchsticks
• 4 tbsp. unsalted butter
• 2 medium yellow onions, thinly sliced lengthwise
• Kosher salt and freshly ground black pepper, to taste
• 1 ¹⁄₂ cups flour
• 2 tsp. dry mustard
• 1 ¹⁄₄ cups milk
• 3 eggs, lightly beaten