Preheat the oven to 350°F and generously spray a Bundt pan with gluten-free nonstick cooking spray.
In a small bowl, combine 1 tablespoon flour with the cinnamon and brown sugar. Set aside.
In a medium bowl, sift together 3 cups flour with the xanthan gum, baking powder, baking soda, and salt. Set aside.
Cream together the butter and granulated sugar in the bowl of a stand mixer fitted with the paddle attachment. Beat in vanilla extract, almond extract, and add eggs one at a time, beating after each addition.
Mix in a third of the flour mixture followed by half the sour cream. Mix in another third of the flour mixture until combined and then the other half of the sour cream. Mix in the remaining flour mixture until combined.
Add a third of the batter to the prepared Bundt pan and spread evenly over the bottom. Evenly sprinkle the batter with half the brown sugar mixture and 1 cup of the blueberries. Add another third of the batter and gently spread evenly around the pan over the blueberries. Evenly spread the rest of the brown sugar mixture and blueberries over the batter. Spread the remaining batter over the blueberries.
Bake for 1 hour or until a cake tester or toothpick comes out clean.
Cool in the pan on a wire rack for 30 minutes, then remove from the pan and cool completely on the wire rack.
To make the glaze, stir together the powdered sugar, cinnamon, vanilla extract, and milk in a small bowl. Drizzle the glaze over the coffee cake and let it set before serving. Store the coffee cake, covered, at room temperature for up to 3 days.