Preheat oven to 350 degrees. Grease and flour an 8" spring form or cake pan or parchment line an 8" spring form or cake pan, then lightly grease. Set aside.
In a medium bowl, combine 1 for 1 gluten free flour, almond flour, tapioca starch, baking powder, baking soda, and salt.
In a separate mixing bowl or Kitchen Aid bowl, put eggs and yolk, together with sugar and maple syrup. Beat on medium high until slightly aerated and a little fluffy.
Add flour mixture, oil, mandarin juice, zest and vanilla. Blend on medium speed of mixer or hand mixer, until well combined and smooth. Add poppy seed and stir in on low. Pour into the prepared pan.
Bake for 25-35 minutes or until a toothpick inserted comes out clean. Cool on a rack for 15 minutes before turning out unto a cake plate.
While cake is cooling, make icing (glaze). Stir ingredients together until smooth.
Once completely cool, split the cake into two layers, by scoring around the edge first, then continuing to cut all the way into the center as you turn the cake. Remove the top of the cake. Drizzle icing on the bottom layer. Replace the top of the cake, then continue to use the rest of the glaze to ice the top of the cake, drizzling icing down the sides and smoothing across the top. I like to use a simple arrangement of fresh (pesticide free and lightly rinsed, then dried) cut flowers. You could also choose to frost with lightly sweetened whipped cream.