Preheat the oven to 350 degrees Fahrenheit and line a muffin tray with muffin papers, or spray the holes with cooking oil.
Mix the eggs, milk, pure maple syrup, almond butter, lemon juice and lemon zest together in a large mixing bowl. Note: if your almond butter is cold from chilling in the refrigerator, microwave it for 30-45 seconds, or until it is very easy to stir. Be sure the wet mixture is completely combined and there are no lumps of almond butter.
Add the oats, gluten-free flour, baking powder poppy seeds, and sea salt and stir well.
Transfer the oat mixture to the prepared muffin tin, filling the holes all the way up.
Bake on the center rack of the oven for 35 to 45 minutes, until the muffins are golden brown and baked through.
Allow the muffins to cool for at least 20 minutes before peeling off the muffin wrappers.
If desired, make the optional glaze by stirring the powdered sugar and lemon juice together in a small bowl until thick and creamy. Drizzle over the muffins and enjoy!