Peach and Blueberry Kuchen

Ingredients

• 2 cups all-purpose flour
• ⅔ cup granulated sugar
• ½ cup sweetened shredded coconut
• 1½ teaspoons baking powder
• ½ teaspoon kosher salt
• 1½ sticks unsalted butter, melted
• ½ teaspoon vanilla extract or vanilla paste
• 4-5 peaches, sliced
• 2 cups blueberries
• ¼ -½ cup granulated sugar, depending on fruit’s sweetness
• 1 teaspoon vanilla extract or paste
• ¼ teaspoon kosher salt
• Juice of ½ lemon
• ½ cup lavender pastry cream (see below)
• 1 cup whole milk
• 1 cup heavy cream
• ¼-½ teaspoon dried lavender buds, crushed between your fingers
• 1 teaspoon vanilla paste, or 1 vanilla bean, split and scraped
• ½ cup plus 1 tablespoon granulated sugar, divided
• 3 egg yolks
• 3 tablespoons cornstarch
• 2 tablespoons unsalted butter
• ½ cup full-fat sour cream or crème fraîche
• 1 egg yolk