Preheat oven to 350 degrees F. Line a muffin tin with muffin papers (I used a stoneware muffin pan)
In a large bowl, whisk together the flour, ground flax seed, baking powder, salt, and lemon zest. Set aside
In a medium bowl, whisk together the rice milk, sugar, and olive oil
Stir the wet ingredients into the dry ingredients and mix well
Scoop the batter evenly into the prepared muffin pan. Each muffin cup will be filled a bit over 3/4 full
Bake for 25-28 minutes until the tops of the muffins have firmed up and spring back a bit when pressed lightly
While the muffins are baking, prepare the glaze: in a small bowl, whisk together the lemon juice and powdered sugar until smooth. Set aside
Cool in the pan for about 5 minutes before removing to a wire rack. Allow the muffins to cool for an additional 10-15 minutes before removing the muffin papers
Drizzle muffins with a bit of lemon glaze and serve