Add milk and mix well. Add egg, butter, and vanilla. Mix well.
Whisk until batter is completely smooth, then add mix-ins. Using a spatula or spoon, gently combine mix-ins.
Place skillet or large pan on stove at medium heat. Add teaspoon of butter to grease the pan.
Wait until butter has fully coated the pan and is bubbling, then add first 1 or 2 pancakes.
A 1/4 cup measuring cup works well to add pancakes to skillet.
Cook on first side until bubble form in the middle, and the edge are no longer sticky.
Flip and cook on second side for another 1-2 minutes.
Repeat until batter is gone.
Notes
For Freezing: Allow pancakes to cool, then stack them 3 high with wax paper squares in between each pancake. Then freeze in ziplock baggies. To Re-heat: Remove pancakes from freezer, separate pancakes and discard wax paper. Place pancakes on a baking sheet and put into a cold oven. Set temperature for 350° and bake for 20 minutes, or until pancakes are warm. Serve as normal.