Preheat the oven to 400 degrees F. Line a (6-cup) jumbo muffin pan with paper liners, or spray with nonstick cooking spray.
Sift the all-purpose flour, baking powder, ground nutmeg, ground cinnamon, and sea salt into a medium mixing bowl. Whisk to combine. Set aside.
Add vanilla bean paste, peach puree, whole milk, and sour cream to small mixing bowl. Whisk to combine. Set aside.
Add unsalted butter, granulated sugar, and light brown sugar to stand mixer bowl. Beat on medium for 3 minutes, or until light and fluffy.
Add egg and egg yolks to mixer. Beat on low until well incorporated.
Remove bowl from stand mixer. Alternate adding half the peach puree mixture and half the flour mixture, folding each in with a large spatula. Avoid over mixing.
Fold in diced peach and fresh blueberries.
Divide the batter evenly between the prepared muffin pan using an ice cream or cookie scoop.
Top each muffin with an equal amount of crumb topping.
Bake 27 to 33 minutes in preheated oven, or until a toothpick inserted in the center of a muffin comes out clean. Tops and edges of the muffin should be golden brown.
Remove muffin tin from oven and cool on wire rack.
Store muffins in an airtight container for several days.