In a food processor, blender, or by hand, mix milk, vegetable oil, 1 tablespoon maple syrup, eggs, flour, baking powder, lemon zest and lemon extract, if desired, until it reaches a smooth consistency. The lemon zest will give the pancakes a subtle, lemony flavor, if you want something stronger, add the lemon extract.
Set aside for 5 minutes.
Warm up a griddle, comal or pan.
Mix frozen berries, the other 2 tablespoons of maple syrup, and the lemon juice (approx 2 tablespoons) and cook on high heat until boiling, then lower temperature to medium high and let it cook for 5 more minutes.
While the berry compote is cooking and when the griddle is hot, oil the surface with butter and pour out 1/4 cup of batter onto the grill, repeat if you have more space. I have a griddle that fits 3 pancakes so that makes my life easier. Allow them to cook for a few minutes, you will know that they are ready to flip when the edges look firmer and beige colored and the whole surface of the pancake is bubbly.
Flip and cook for a few more seconds until bottom is golden. Repeat until you finish with all the batter.
Serve hot with the berry compote and maple syrup if you like and a big cold glass of milk.