French Toast with Berry Butters

INGREDIENTS

• 4 whole egg yolks
• 2 cups half-and-half
• 1 loaf crusty bread, such as baguette, French loaf, etc.
• Sifted powdered sugar, for serving, optional
• 1/2 cup raspberries
• Zest of 1 lemon
• Maple syrup, warm, for serving
• 1/2 cup blackberries
• Butter, for frying
• 2 teaspoons vanilla extract
• 1 pound (4 sticks) unsalted butter, softened
• 1 tablespoon sugar