Measure out the milk. Add the vinegar. Allow to sit for about 5 minutes. If you have buttermilk you can use ¾ cup of that instead. I love buttermilk but I rarely have any so I just do it this way.
In a bowl, combine the flour, the sugar, the baking powder, the baking soda, pumpkin pie spice and the salt.
After five minutes has passed, whisk the egg and the butter into the soured milk. Add the canned pumpkin and whisk again.
Pour the flour mixture into the pumpkin mixture whisk until lumps are gone. At this point, you can see whether you need more liquid or more flour. (this will probably depend somewhat on how much pumpkin you used) Add milk and/or flour by Tablespoons until you are happy with the consistency. (usually I just leave it as is, but in case you like a different texture batter).
Mix in the cup of chopped apple.
Heat a large skillet over medium heat or a griddle set to 360 degrees, and coat with cooking spray. Pour ¼ cup of batter onto the skillet or griddle, and cook until bubbles begin to appear on the surface.
Flip ONLY once with a spatula, and cook until golden on the other side.
Remove from griddle/skillet and serve.
Top with whipped cream and some pumpkin pie spice or syrup.