Lemon Poppy Seed Cake | Saveur

Ingredients

• Nonstick spray or vegetable oil
• ¼ cup poppy seeds, divided, plus more for garnish
• 1½ cups (260g) all-purpose flour
• ⅔ cup whole or low-fat buttermilk, shaken well
• 1 Tbsp. vanilla bean paste or vanilla extract
• 16 Tbsp. cold unsalted butter, cut into cubes
• ¾ cup sugar, divided
• 2 Tbsp. finely grated lemon zest
• ¾ tsp. baking soda
• ¾ tsp. kosher salt
• ¼ tsp. cream of tartar
• 4 extra-large egg whites
• 1 cup powdered sugar, plus more as needed
• 1 Tbsp. plus 2 tsp. whole milk
• 1 tsp. fresh lemon juice