Preheat the oven to 400 degrees. Generously spray muffin tins with Pam. Pare the apples and cut each piece into 8 wedges. Slice each wedge crosswise into thin slices. Combine 2 tablespoons of the sugar with the cinnamon and toss the apples with this mixture and set aside.
Combine the flour, sugar, baking powder and salt and stir with a wire whisk until well- blended. Add the melted butter to the next three ingredients (eggs through sour cream) and mix well. Pour this mixture into the dry ingredients along with the apples and mix until just combined. (The batter will seem very dry. Be careful not to over-mix, as this will cause the batter to overflow. As soon as you start to think that you should just stir a couple times more---DONT) Divide the batter evenly between 10 muffin cups. Sprinkle the sliced almonds on top. Bake the muffins in the center of the oven for approximately 20 to 25 minutes.
While the muffins are baking, combine the apple jelly and water and slowly bring to a boil, stirring occasionally. Keep this mixture warm until ready to use. When you remove the muffins from the oven, place them on a wire rack for five minutes before removing them gently from the pan. Brush the muffins with the melted apple jelly and serve them warm or cold.
These muffins freeze well after baking. Reheat them before serving.