• Preheat your oven to 350 degrees Fahrenheit and grease a 9 inch cake pan with vegetable oil. Line the bottom with parchment paper and lightly grease the parchment paper as well. Set aside.
• In a large bowl, whisk together the 1 ¾ cups gluten free flour, 2 teaspoons of baking powder and ½ teaspoon kosher salt. Set aside. 
• In a small bowl, using a spoon, mix together the 4 rounded tablespoons of cornstarch with 6 tablespoons of water until thin and watery. It will be thick and tacky at first. Set aside.
• In a large bowl of an electric mixer fitted with the paddle attachment, beat the ½ cup butter or vegan baking stick and the ½ cup granulated sugar until it is all soft and creamy. About 2-3 minutes.
• Slowly beat the cornstarch water mixture, the ¾ cup maple syrup and the 1.5 teaspoons of vanilla, a little at a time, into the creamed butter and sugar. It will look chunky and curdled; that's normal.
• Starting and ending with the gluten free flour mixture, with the mixer on low...beat in some flour then some milk then some flour.

  Once it is combined, turn off the mixer and use a spatula to scrape the sides of the bowl. You don’t want to over mix this. Just make sure everything is fully combined.
• Using a spatula, scoop the batter in a greased and parchment lined 9 inch cake pan; smooth the top with a butter knife. It will be super thick and sticky.

  Bake the cake in the center rack at 350 degrees Fahrenheit for 42 minutes until the cake is golden on top and springs back at you when careful touched.
• Let the cake cool completely in the cake pan. If you try to take it out when it is even a tiny bit warm, the entire thing may fall apart.

  Once cool, move to a cooling rack.  If it seems to be sticking to the cake pan, use a butter knife or a spatula to loosen the edges.

For the Maple Frosting

• While the cake is baking, make the frosting.

  In the large bowl of an electric mixer or using a hand held mixer, beat the 4 tablespoons butter and the 2 tablespoons light brown sugar until smooth and creamy. About 2-3 minutes.
• With the mixer on very low speed, slowly beat in the 2 ½ cups confectioners' sugar and ⅓ cup plus 2 tablespoons maple syrup until combined.

  Slowly beat in the 1.5 teaspoons of water a little at a time until you get the desired consistency. You may not need to use all the water.
• Using an icing spatula or a butter knife, frost the sides and top of the cake.

  To make pretty swirls or designs, use the icing spatula, the back of a spoon or a butter knife.