Preheat the oven to 375°F (190°C). Grease and fully line a 9x5-inch loaf pan with parchment paper.

In a medium bowl, whisk together the flour, granulated sugar, and salt for the streusel. Add the cold plant butter and vanilla bean paste. Work together with your fingertips until a mixture of fine crumbs and large buttery clusters forms. Refrigerate while preparing the batter.

In a large bowl, whisk together the brown sugar, granulated sugar, oil, yogurt, vanilla bean paste, mashed banana, milk, and apple cider vinegar until completely smooth.

Add the all-purpose flour, cornstarch, baking powder, baking soda, salt, and nutmeg. Whisk just until combined. Do not overmix.

Spread just under half of the batter into the prepared loaf pan.

Sprinkle half of the chilled streusel evenly over the batter.

Carefully spread the remaining batter over the streusel until completely covered.

Sprinkle the remaining streusel evenly over the top, leaving plenty of large buttery clusters.

Sprinkle the top lightly and evenly with coarse sanding sugar just before baking.

Bake at 375°F for 10-12 minutes.

Without opening the oven, reduce the temperature to 350°F (175°C) and continue baking for 45-55 minutes. Tent loosely with foil if the streusel begins browning too quickly. The loaf is done when a tester inserted into the cake portion comes out with moist crumbs or the center reaches 205-210°F (96-99°C).

Cool in the pan for 20 minutes, then lift out and cool completely on a wire rack.

Whisk together the powdered sugar, milk, vanilla bean paste, and salt until completely smooth. Add additional milk a teaspoon at a time if needed until the glaze ribbons off the whisk but is not watery.

Spoon or pour the glaze generously over the top, letting it run naturally down the sides.

Immediately sprinkle lightly with clear coarse sanding sugar for extra crackle.

Allow the glaze to set on the counter or in the refrigerator before slicing.