Iced Corn Coffee Cake From 'Savory Baking'

Directions

1. Preheat the oven to 400°F/205°C with the oven rack in the center. Lightly grease an 8x8 in/20x20 cm pan with nonstick spray.
2. In a medium bowl, mix the flour, oats, brown sugar, cornmeal, salt, and cinnamon to combine. Add the cold unsalted butter, and use your hands to rub the butter into the mixture until it forms moist crumbs. Set aside.
3. In a medium bowl, whisk the melted butter and oil together to combine. Add the egg and brown sugar (if using), and whisk well to combine.
4. In a medium bowl, whisk the cornmeal, flour, baking powder, and salt until well combined.
5. Add half of this mixture to the bowl with the butter/oil and mix with a silicone spatula to combine. Add half of the buttermilk, mixing with the spatula to incorporate. Repeat this process, adding the remaining flour and buttermilk and mixing just until the ingredients are uniformly combined.
6. Pour the batter into the prepared pan and spread into an even layer. Sprinkle the streusel in an even layer over the batter. Bake for 18-20 minutes, until the edges are golden brown and a toothpick inserted into the center comes out clean, or with a few moist crumbs.
7. Cool at least 30 minutes before slicing to serve warm, or cool completely and serve at room temperature.
8. Just before serving, whisk the icing ingredients to combine. The mixture should be thick, but drizzle-able. Drizzle over the coffee cake.