Peach-Almond Upside-Down Cake

INGREDIENTS

• 1/2 teaspoon vanilla extract
• 1 1/2 cups all-purpose flour
• 1/2 cup whole almonds
• 2 teaspoons baking powder
• 2 large eggs
• 1 1/2 cups sugar
• 1 stick unsalted butter, at room temperature, plus more for the pan
• Vanilla ice cream, for serving (optional)
• 3/4 cup whole milk
• 4 medium peaches or nectarines, pitted and cut into 6 wedges each
• 1/2 teaspoon salt
• 1/4 teaspoon almond extract