Preheat your oven to 400°F. Line a 12-cup muffin tin with paper liners and set aside.

In a large bowl, sift together 3 cups of flour, baking powder, nutmeg, and salt, then set aside.

Using an electric mixer or a stand mixer with the paddle attachment, beat the butter and sugars on medium speed until light and fluffy, about 3 minutes.

Add the egg, egg yolks, and vanilla to the mixture, continuing to beat until well combined.

Reduce the mixer speed to low and alternately add the flour mixture and milk, starting and ending with the flour. Be careful not to overmix.

Turn off the mixer and set the batter aside. In another bowl, toss the raspberries and peach pieces with the remaining 2 tablespoons of flour until the fruit is fully coated.

Gently fold the fruit into the batter using a spatula until well incorporated. It's okay if the raspberries break up a little.

Divide the batter evenly among the prepared muffin tins.

Bake for 20 to 22 minutes, or until the tops are lightly golden brown and a toothpick inserted in the center comes out clean or with just a few moist crumbs. Allow the muffins to cool in the pan for 10 minutes before transferring them to a cooling rack.

In a small bowl, combine the confectioners' sugar, vanilla, and cream. Whisk until smooth, adding more cream as needed to reach your desired consistency. Drizzle the glaze over the muffins just before serving.