Preheat your oven to 375°F (190°C).
Prepare a muffin tin by greasing wells or lining it with paper liners.
In a large mixing bowl, combine flaxseed and oat milk. Stir them together, then let the mixture rest for 5 minutes.
Rinse, pat dry, and halve the blackberries.
In a small bowl, coat the blackberries with 1 tablespoon of flour to coat them. This helps prevent the berries from sinking in the muffin batter.
Add maple syrup, oil, and vanilla extract to the flaxseed mixture. Stir until the mixture is smooth and well combined.
Add lime juice and zest, mixing well.
Stir in baking powder and salt into the wet mixture.
Gently stir in the flour until just combined, being careful not to overmix.
Carefully fold in the flour-coated blackberries into the batter.
Spoon the batter into the prepared muffin tin, filling each well to about ½ inch below the top.
Place the muffin tin in the preheated oven and bake for 25-30 minutes, or until a skewer inserted into the center of a muffin comes out clean.
After baking, allow the muffins to cool in the pan for at least 10 minutes before removing them. This helps them set and makes them easier to remove without breaking.
How to Store Blackberry Lime Muffins
These muffins are best enjoyed the same day they are made. However, if you have leftovers, store them in a sealed container in the refrigerator for up to 2 days.
Reheat them in the oven before serving for the best taste and texture.