Raspberry Peach Muffins

Ingredients

• 1 cup raspberries (fresh or frozen (if using frozen, do not thaw))
• 3 teaspoons baking powder
• 1/2 teaspoon salt
• 1 large peach (peeled and chopped into bite-sized pieces)
• 3 cups plus 2 tablespoons all-purpose flour (divided)
• 1 cup granulated sugar
• 6 tablespoons unsalted butter (at room temperature)
• 2 teaspoons pure vanilla extract
• 1 cup whole milk
• 1 large egg plus 2 large egg yolks
• 1/4 teaspoon ground nutmeg
• 1/4 cup light brown sugar (packed)
• 1 cup confectioners' sugar
• 1/2 teaspoon vanilla extract
• 2 tablespoons milk or heavy cream (more if needed for desired consistency)