Preheat oven to 350 degrees. Grease muffin cups or use paper liners. Blend 3/4 cup brown sugar, oil, eggs, and vanilla in a large bowl. Combine flour, baking soda, salt, and spices. Add to wet mixture.
Add apple and buttermilk and mix thoroughly just to moisten. Fill muffin cups 2/3 full. Combine 1/4 cup sugar, pecans, and cinnamon in a small bowl for topping. Sprinkle evenly over batter. Bake at 350 degrees for 20 to 25 minutes.
1/4 cup brown sugar
1/4 cup chopped pecans
1/2 teaspoon cinnamon