½ cup vegetable oil
2 tsp. vanilla
1 1/3 cup packed light brown sugar
2 ½ cups all-purpose flour
¼ tsp. salt
2 ½ tsp. baking powder
½ tsp. baking soda
1 ¾ cups coarsely chopped peeled apples
1 cup buttermilk
1 Tbsp. cold butter
1/3 cup firmly packed brown sugar
½ tsp. cinnamon
½ cup finely chopped walnuts
2 Tbsp. butter
¼ cup light brown sugar
2 Tbsp. milk
1 tsp. vanilla
1 cup powdered sugar
1. In a bowl, combine all the streusel ingredients. With your fingers, combine until you have a crumbly mixture. Set aside.
2. Preheat the oven to 400 degrees and line 18 muffin cups with paper liners.
3. In a bowl, mix together the dry ingredients; set aside. In another bowl, combine the oil, brown sugar and egg. Once combined, stir in the buttermilk and vanilla.
4. Add the wet ingredients to the dry ingredients and mix well. Gently mix in the apple. The batter should be fairly stiff. The original recipe indicated "if the batter seems too thin, add a tiny bit more flour." No measurements (probably due to difference in climate, etc.) provided. I felt mine turned out well as is. I did read some folks added up to another ½ cup. Spoon the batter in the muffins cups, filling about ¾ full.
5. Divide the streusel topping equally among the muffins.
6. Bake for 5 minutes and then lower the temp to 350 degrees and bake for an additional 15-20 minutes, or until the muffins spring back when gently pressed. Let the muffins cool in the pan for approximately 10 minutes; remove and let cool for an additional 20 minutes on a wire rack before icing.
7. While muffins are baking, prepare the caramel drizzle mixture. Combine brown sugar, butter and milk in a medium size microwave-safe bowl. Microwave on high for 30 seconds, add vanilla, stir well and return to the microwave for about 15 seconds.
8. Add powdered sugar and mix vigorously until smooth and creamy. Drizzle over cooled muffins.
* I think next time I'm going to increase the streusel topping; I felt like I could have used a bit more on each of the muffins. I'll probably increase the ingredients by another 50%.