In a large bowl, combine all the dry ingredients - gluten free flour, baking powder, baking soda, sugar, salt, lemon zest and poppy seeds. Mix until well combined.
Add the frozen butter to the dry ingredients and work together quickly until all the butter is coated with the flour mixture.
In a small second bowl, crack your egg and egg yolk. Whisk until frothy.
Add the honey, milk and lemon juice to the egg yolk. Mix together.
Slowly add the liquid to the dry ingredients (I usually add half at a time). Toss together so the liquid is evenly incorporated. Work until the dough is a shaggy mess, just holding together.
There should be a small amount of liquid leftover, less than 1 Tbsp. Reserve this to brush on top of the scones before baking to give a nice golden brown color to the top.
Turn your dough out onto a piece of parchment paper and gently press it together into a round disk about 1 inch thick. With a sharp knife or bench scraper, divide your circle into 8 wedges (like pizza slices). Place the wedges on a lined baking sheet leaving ¼" to ½" between each wedge.
Places scones into the refrigerator to chill for 30 minutes.
Preheat oven to 425 degrees F.
Remove your scones from the refrigerator. Brush the tops with the remaining liquid from the recipe, taking care not to brush the sides. Place directly into the hot oven.
Bake 23-25 minutes until the inside is done.
Remove from oven and cool about 15 minutes before adding the icing.
For the icing
In a small bowl, combine powdered sugar, lemon juice, milk and lemon zest. Stir until smooth.