Preheat your oven to 425°F. Line two jumbo 6-cup muffin pan with 8 paper liners or generously grease each cavity with nonstick baking spray.
In a medium bowl, combine the melted butter, all purpose flour, light brown sugar, sliced almonds, cinnamon, and a pinch of salt. Mix with a fork until large buttery crumbs form. Place the crumble in the refrigerator while preparing the batter.
In a large mixing bowl using a handheld mixer, beat the softened butter, light brown sugar, and granulated sugar together until light and fluffy.
Add the mashed bananas and mix until combined. Beat in the eggs one at a time, then mix in the vanilla bean paste and sour cream until smooth.
In a separate bowl, whisk together the almond flour, all-purpose flour, baking powder, baking soda, cinnamon, and salt.
Gradually fold the dry ingredients into the wet ingredients just until no streaks of flour remain. Do not over-mix, as this can make the muffins dense.
Divide the batter evenly between the six jumbo muffin cups, filling each nearly to the top.
Generously sprinkle the chilled almond crumble over each muffin, gently pressing it into the batter so it adheres during baking
Bake at 425°F for 5 minutes. Without opening the oven door, reduce the temperature to 350°F and continue baking for 25–30 minutes, or until the tops are golden brown and a toothpick inserted into the center comes out with just a few moist crumbs.
Allow the muffins to cool in the pan for 10 minutes before transferring them to a wire rack to cool completely.
In a small bowl, whisk together the powdered sugar, 1 tablespoon milk, and Rising Star cinnamon syrup. Add additional milk, a teaspoon at a time, until the glaze reaches your desired consistency.
Drizzle generously over the cooled muffins before serving.