In a large mixing bowl, combine flour, baking powder, salt, and black pepper.
In a separate bowl, beat eggs and then stir in milk and melted butter.
Slowly pour the wet ingredients into the dry ingredients, whisking or stirring until just combined.
Fold in chopped spinach and crumbled feta cheese.
Heat a non-stick skillet or griddle over medium heat and lightly grease with olive oil.
Use a 1/4 cup measuring cup to scoop pancake batter onto the skillet and cook for 2-3 minutes, until bubbles appear on the surface.
Flip the pancakes and cook for an additional 2-3 minutes on the other side, until golden brown.
Remove pancakes from the skillet and place on a plate lined with paper towels to absorb any excess oil.
Serve warm with your choice of toppings, such as sliced avocado or a dollop of sour cream.