Whisk Flour, Cocoa Powder, Sugar, And Salt Together In A Large Bowl. Beat Eggs, Milk, And Vanilla In Another Bowl; Mix In The Melted Butter. Pour The Wet Ingredients Into The Dry, And Mix Just Until Combined. Stir In The Chocolate Chips. Heat A Lightly Oiled Griddle Or Skillet Over Medium-High Heat. For Each Pancake, Pour 1/4 Cup Batter On Griddle And Cook Until Bubbles Pop In The Center Of The Pancake, About 2 To 3 Minutes. Flip, And Cook An Additional Minute On The Opposite Side.