Preheat the oven to 350°F (180°C) and prepare the muffin tins.
Mix the flour, chia seeds, baking powder, baking soda, and salt together in a bowl.
In a separate bowl, mix together the eggs, sugar or honey, milk, oil, and vanilla.
Pour the wet ingredients into the dry mixture and stir to combine.
If you'd like, add the blueberries or chocolate.
Divide the batter evenly among the muffin tins.
Bake for 18 to 22 minutes, until golden brown.
You can vary them with matcha powder, grated apple and cinnamon, or lemon zest and poppy seeds for an even more special muffin.