Oil an 8 x 4 x 2-1/2-inch loaf pan; line with parchment paper, extending about 1-inch above the rim of the pan, set aside.
In a small bowl, whisk the gluten-free flour, baking soda and baking powder, set aside.
In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter, sugar, and salt on medium speed. Scrape the sides and bottom of the bowl as needed. Beat until light in color and fluffy, about 5 minutes.
Add the lemon zest, juice and vanilla and lemon extract and mix until combined. Add the eggs 1 at a time until it’s fully incorporated and fluffy. Add the buttermilk and mix until combined. Add dry ingredients and start on a low speed until it’s fully incorporated. Increase to medium speed and mix for about 1 min until the batter is smooth and no lumps.
Transfer the batter into the prepared pan smooth out the top with a rubber spatula.
Bake until a wooden stick inserted near (not in) the center comes out clean and the cake springs back when lightly touched.
Remove the pan from the oven and set on a wire rack to cool for 10 minutes or until the cake is cool enough to handle.
Remove the cake from the pan, remove the paper, and allow the cake to cool directly on the wire rack.
Make the glaze: Combine all the ingredients in a medium bowl and use a whisk to combine until smooth. Add additional powdered sugar 1 tbs at a time until desired consistency is achieved.
Pour over cooled Lemon Pound Cake and let the glaze harden before cutting.