This recipe was adapted from The SoNo Baking Company Cookbook's Banana Streusel Muffins.
1/2 cup all-purpose flour
1/2 cup light brown sugar
1/4 teaspoon coarse salt
1/8 teaspoon ground cinnamon
1/4 cup cold unsalted butter, cut into small cubes
2 cups all-purpose flour
1 teaspoon baking powder
1 teaspoon baking soda
1/2 cup unsalted butter, at room temperature
1 cup granulated sugar
1 1/2 teaspoons coarse salt
2 large eggs, at room temperature
2 teaspoons pure vanilla extract
1 1/2 cups apples (about 2 medium apples), peeled and chopped
18 Kraft caramels, unwrapped and quartered
3/4 cup sour cream or whole-milk yogurt
Make the streusel topping: In a medium bowl, use a fork to stir together 1/2 cup flour, brown sugar, 1/4 teaspoon salt, and cinnamon. Add the 1/4 cup cubes of butter, and using your fingertips or a pastry cutter, work it into the dry ingredients until pea-size crumbs form; set aside in the refrigerator.
Set the oven rack in the middle position. Preheat the oven to 375°F (190°C). Spray a standard 12-cup muffin pan with nonstick cooking spray and line with FOIL liners; set aside.
Make the muffins: In a medium bowl, whisk together 2 cups flour, baking powder, and baking soda; set aside.
In the bowl of a standing mixer fitted with the paddle attachment, beat the 1/2 cup butter, sugar, and 1 1/2 teaspoons salt on medium-high speed until light and fluffy, 2 to 3 minutes, scraping down the sides of the bowl halfway through. Add the eggs one at a time, beating after each addition. Then add in and beat the vanilla.
With the mixer on low speed, add the dry ingredients, beating until the flour is absorbed. Beat in the sour cream. Fold in the apples and caramels.
Divide the batter evenly among the prepared muffin cups (fills 12-16 muffin cups). Sprinkle the streusel topping over the muffins, pressing some of the mixture into pea-size clumps with your fingertips, for added texture.
Bake, rotating the pan about two-thirds of the way through the baking time, until the tops of the muffins spring back when touched and a cake tester inserted in the center of a muffin comes out clean (with maybe a little caramel on it), 18 to 22 minutes.
Transfer the pan to a wire rack to cool for 10 minutes. Loosen muffins from the pan carefully and transfer to another wire rack to cook, or eat them while the caramel is gooey!
Use foil muffin liners, not paper.
Spray top of the muffin pan so muffin tops don't stick.
Recipe by 5 Minutes for Mom at http://www.5minutesformom.com/65988/caramel-apple-streusel-muffins/