Ingredients

• cooking spray
• 2 medium meyer lemons, scrubbed and divided, plus thin slices, for garnish
• 1 1/4 cups granulated sugar
• 1/2 cup packed light brown sugar
• 1/2 cup unsalted butter (4 ounces), melted
• 1 large egg
• 2 1/4 cups all-purpose flour (about 9 1/2 ounces)
• 1 teaspoon baking powder
• 1 teaspoon kosher salt
• 1 1/4 cups powdered sugar, divided