Preheat oven to 325°F and place a rack in the center of the oven.
Thoroughly grease your pan whether it's a bundt, loaf, or other.
In a medium bowl, sift together gluten free flour, salt, baking powder. Whisk in sugar and poppyseeds, set aside.
In a large bowl, mix together eggs, milk, oil, and flavorings. When thoroughly mixed, whisk in the dry ingredients. If the dough is too thick, add in additional milk, 1 tbsp at a time. We are looking for thick pancake batter consistency.
Pour cake mix into the cake pan and tap a few times to release any air bubbles. Set in oven and bake for 1 hour or until a toothpick inserted comes out clean.
For the Icing
Sift powdered sugar together in a large bowl. Add in lemon juice and milk. The icing should have a thickness to it and not be too runny. Let sit on counter to firm up while the cake is baking.
Remove cake from oven and let cool on wire rack for at least 10 minutes before removing. Once removed from pan, let cool completely before adding icing.
Pour icing over and let it naturally run off the sides. Sprinkle lemon zest on top for a garnish.
Make sure to store the cake in an air tight container to retain it's moisture. If you want to freeze it, cut it into smaller portions, wrap in plastic wrap and then place in a freezer ziplock bag. Let it come to room temperature on the counter to reheat if desired.