For the Filling:

• 1 cup all-purpose flour
• 1/2 cup sugar (plus extra for sprinkling on top)
• 1/4 teaspoon salt
• 2 large eggs
• 1/2 cup milk (whole milk works best, but any kind is fine)
• 1/2 cup unsalted butter, melted and slightly cooled
• Zest of 1 large lemon
• Juice of 1 large lemon (about 2–3 tablespoons)