This might just be one of the best cakes I have ever had. Seriously, I had a hard time shooting it because I wanted to eat the whole thing right then and there. I added tapioca starch to the quinoa flour and the texture was so tender and perfect. I reduced the sugar by 1/3 in the cake along with changing all ingredient amounts and the prep method(using melted butter instead of solid), and added milk. This is THE most tender cake I have ever had.
In a large mixing bowl, whisk together the quinoa flour, tapioca starch, sugar, baking soda, baking powder, and salt until combined.
Pour the melted butter, eggs, and sour cream into the bowl of dry ingredients and whisk together until combined. Add the milk and whisk until smooth. Pour the batter into the greased baking pan.
In the bowl of a stand mixer, beat the softened butter with the browned sugar, quinoa flour, and cinnamon until smooth. Scoop into a piping bag and cut the tip off(about ¼”). Pipe the cinnamon sugar/butter over the cake batter in swirls.
Bake the cake in the preheated oven for 35-40 minutes, or until the middle is puffed and firm to the touch.
While the cake is baking, make the glaze.
In a mixing bowl, whisk the powdered sugar with the vanilla and milk until smooth, adding more or less milk for the preferred consistency.
Remove the cake from the oven.
Let cool for 5 minutes and drizzle the glaze across the top.
The quinoa flour will give the cake a very yellow color.