Preheat your oven to 350 degrees. Line or spray 12 muffin tins.
In a medium mixing bowl, combine the flour, ground flaxseed, baking powder, baking soda, ground cinnamon, ground cloves, ground allspice, ground cardamom, ground nutmeg and salt. Set aside.
In a large mixing bowl, whisk together the eggs and brown sugar for 30 seconds.
Add in the canola oil, pumpkin puree, milk and vanilla extract. Whisk until combined. Whisk in the lemon zest.
Pour the dry ingredients into the wet mixture and fold together until just combined. Don't overmix or you'll end up with tough, dense muffins.
Divide the batter among 12 muffin tins and bake for 20-23 minutes or until a toothpick comes out clean.
Let the muffins cool in the tins for 5 minutes then fully cool on a cooling rack. Store in an airtight container for up to 3 days or in the freezer for up to 3 months. Enjoy!!