Preheat the oven to 325.
To make the dough, add all the dry ingredients to a large bowl and mix well.
Add in the butter and using a fork or pastry blender, work in the butter until it has broken down to pea sized.
In a small bowl, gently whisk the egg and egg yolk. Add the eggs, lemon juice and zest to the scone batter and mix well. The dough should be holding together at this point.
Add in the chia seeds, and mix until evenly dispersed.
Line a cookie sheet with parchment paper and sprinkle it with tapioca starch. Pour out the dough onto the cookie sheet, and sprinkle with a bit more tapioca flour on top. Pat the dough into a circle, about 7-8 in round.
With a very sharp knife, cut a “plus sign” into the dough, creating 4 sections. Now, cut each section into 2 triangles. Think of cutting a “plus sign” then an “X”. Do not move the individual scones at this point. Since these are grain-free, the dough is too fragile for moving.
Place in the oven and bake for 20 min.
While the scones are baking, add all the frosting ingredients to a small bowl and whisk until smooth.
The scones are not quite finished baking yet. At this point, remove the scones from the oven, and carefully take a knife and run it down the cuts you previously made. Gently separate the scones away from one another. Then bake for another 6-8 minutes.
Allow to cool, then generously frost the scones.