Preheat the oven to 350 degrees Fahrenheit and line a 12-cup muffin tin with paper baking cups.

In a medium bowl, whisk together the ground flaxseed, psyllium husks, and lemon zest. Then mix in all the wet ingredients and set aside.

In a large bowl, whisk together all the dry ingredients (through salt). Add the wet ingredients to the dry ingredients and mix with a rubber spatula. (The batter will be thick.) Fold in the blueberries.

Using an ice-cream scoop or measuring cup, drop about 1/4 cup of batter into each baking cup. Bake for 30 to 35 minutes, or until golden brown and a toothpick or fork inserted in the center of a muffin comes out clean.

Remove from the oven and allow to cool for 10 minutes in the pan, then transfer to a wire rack to cool completely.

Serve immediately, or store in an airtight container at room temperature for up to 3 days or in the fridge for 1 week. Bring back to room temperature or toast before serving.