Preheat the oven to 350°F. Grease a standard 9x5-inch loaf pan and fully line it with parchment paper.

Make the streusel. In a medium bowl, whisk together the flour, sugar, and salt. Add the cold cubed butter and vanilla bean paste. Work the mixture together with your fingertips until fine crumbs and large buttery clusters form. Refrigerate while you prepare the batter.

In a large bowl, whisk the granulated sugar, brown sugar, oil, yogurt, vanilla bean paste, 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. Scatter about half of the chilled streusel over the batter in an even layer.

Add the remaining batter and gently spread it to fully cover the streusel. Do not fill the loaf pan more than ¾ full, even if some batter remains. Top generously with the remaining streusel, keeping the texture loose and clustered; do not press down.

Sprinkle generously with clear coarse sanding sugar before baking.

Bake at 350°F for 55-65 minutes, or possibly longer if your oven runs slower. Check the loaf at 45 minutes and tent it loosely with foil if the streusel is browning quickly.

Use the toothpick test as the main guide: a tester inserted into the cake portion, not through the streusel seam, should come out with moist crumbs, not wet batter. Temperature is a helpful baseline, usually around 205-210°F in the cake portion.

Cool the loaf in the pan for 20 minutes, then use the parchment to lift it onto a wire rack and cool completely.

Make the glaze. Whisk the powdered sugar, milk, vanilla bean paste, and salt until completely smooth and the glaze ribbons off the whisk without becoming watery.

Spoon or pour the glaze generously over the cooled loaf, allowing it to run naturally down the sides.

Allow the glaze to set before slicing.