In a large bowl, sift or whisk together the flour, baking powder, cinnamon, nutmeg, cardamom, and salt.
In a separate bowl, stir together the mashed banana, plant milk, oil (or applesauce if you want to avoid using oil), brown sugar, and vanilla extract until smooth.
Add the wet mixture to the dry ingredients and whisk just until the batter is uniform with no visible dry flour. Avoid overmixing.
Set a nonstick or cast iron skillet or griddle over medium heat. After 2 minutes when the oil or vegan butter is hot, ladle ¼ cup (60 mL) of batter into the skillet for each pancake.
While the pancakes are cooking on the first side, you can optionally (I recommend it!) push several banana slices down into the surface of each pancake.
Cook over medium heat for 2 to 3 minutes, or until the edges are set and bubbles form across the surface. Flip and cook for 2 minutes on the second side, or until golden and fully cooked.
Transfer to a warm plate and repeat with the remaining batter and banana slices, adding more oil or vegan butter as needed.
Serve warm with maple syrup, vegan butter, vegan whipped cream, and toasted walnuts.