Preheat your oven to 350°F (175°C) and line a 12-cup muffin tin with paper liners or grease it lightly.
In a large mixing bowl, combine the dry ingredients: flour, sugar, baking powder, baking soda, and salt. Mix well.
In a separate small bowl, whisk together the wet ingredients: non-dairy milk, vegetable oil, maple syrup, and vanilla extract. If using flaxseed meal, add it to the wet ingredients.
Pour the wet ingredients into the dry ingredients and stir gently to combine. Avoid overmixing to keep the muffins light and fluffy.
If desired, fold in fruit, chocolate chips, or any other additions.
Use a spoon or ice cream scoop to divide the batter evenly into the muffin tin, filling each cup about 2/3 full.
Bake for 18-22 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Let the muffins cool in the tin for 5 minutes before transferring to a wire rack to cool completely.