Preheat oven to 350F and line a 9’’x4’’ loaf pan with parchment paper.
In a large bowl, sift together gluten-free flour, almond flour, xanthan gum, baking powder, sugar, and salt. Give them a mix
Add softened butter and mix with a hand mixer until the texture resembles coarse crumbs.
Stir in grated lemon zest.
In another bowl, whisk together eggs, Greek yogurt, vanilla, and lemon juice.
Add wet ingredients to dry and mix until smooth and fully combined.
Transfer batter to the loaf pan and smooth the top.
Bake for 55-60 minutes, until golden, and a toothpick comes out clean (cover with foil if it starts browning too quickly).
Cool in the loaf pan for 10 minutes, then transfer to a rack to cool completely.
Optional: Make the lemon glaze. Mix powdered sugar and lemon juice until smooth. Adjust consistency as needed.
Drizzle over cooled cake and let it set before slicing. Serve.