Preheat oven to 425°F and grease 2 standard muffin tins (12 cups each) or line with paper muffin cups.
Place all of the ingredients for the pecan streusel topping in a medium bowl. Using a pastry cutter or your fingers mix the butter into the dry ingredients until you have a mixture resembling coarse crumbs. Set aside. (Note: you can also use a small food processor/mini chopper)
1/4 cup pecans, 1/4 cup flour, 3 tablespoon butter, 3 tablespoon quick oats, 3 tablespoon brown sugar, 3 tablespoon sugar, 1 1/2 teaspoon cinnamon
In a large bowl, whisk together the flour, cinnamon, baking soda, baking powder, salt, nutmeg and cloves
In a medium bowl mix together the sour cream, caramel topping, and vanilla; set aside.
3/4 cup sour cream, 1/2 cup caramel topping, 2 teaspoon vanilla
In the bowl of a stand mixer cream together 1/2 cup brown sugar and the butter.
3/4 cup butter, 1/2 cup brown sugar
Beat in egg yolks one at a time, mixing completely after each addition.
3 eggs
Set your mixer on low and alternate adding flour and caramel mixtures. Mix just until combined; do not over mix - some small dry pockets, lumps or streaks of flour are expected at this stage.
In as few strokes as possible, fold in the apple and flour mixture.
1 1/2 cup apple
In another bowl beat the egg whites until soft peaks form. Continue beating while gradually adding the remaining 1/4 cup sugar. Beat until stiff and glossy.
3 eggs, 1/4 cup sugar
Fold 1/3 of the egg whites into the batter to lighten it. Gently fold in the remainder of the egg whites just until no white streaks remain.
Spoon the batter into the prepared muffin tins filling about 3/4 full, leaving just enough room for the streusel topping.
Sprinkle about 1 tbsp of streusel topping over the batter in each cup.
Place the pans in the heated oven for 5 minutes. Then, without opening the oven door, reduce the temperature to 350°F and back for an additional 16-18 minutes or until the tops are golden brown and a toothpick inserted in the center of a muffin comes out with a few moist crumbs.
Store in a sealed container.
Notes
Greek yogurt or butter milk may be substituted for the sour cream.For a simpler version of the recipe, add whole eggs to the creamed butter and sugar mixture. This avoids the need to separately whip the egg whites and fold them in, but the texture of the muffins will be a bit less fluffy.