Preheat the oven to 425 and line a 12-cup muffin pan with cupcake liners.
In a medium bowl whisk together the flour, xanthan gum, sugar, poppy seeds, baking powder, salt and baking soda.
In large mixing bowl whisk together the oil, lemon juice, lemon zest, eggs, milk, vanilla, and apple cinder vinegar. Do not use electric mixer.
Using a spatula add in the flour mix and stir until smooth and combined. Do not over mix.
Divide the batter evenly into the muffin pan and bake for 5 minutes.
Without opening the oven door, reduce the temperature to 350 and bake another 18-20 minutes until the tops are slightly golden and a toothpick inserted into the center of one muffin comes out clean.
Let the muffins cool in the muffin pan for 5-10 minutes, then transfer them to a wire rack to cool completely.
Serve and enjoy.