Apple Butter Muffins

Name: Apple Butter Muffins
Prep time: 20 min
Cook time: 20 min
Total time: 40 min
Cuisine: American
Ingredients: 2 cups all-purpose flour (260 grams); 1/2 cup granulated sugar (100 grams); 1 teaspoon baking powder (4 grams); 1 teaspoon baking soda (5 grams); 1 teaspoon cinnamon (2 grams); 1/2 teaspoon salt; 1 large egg; 3/4 cup milk (6 ounces); 1/2 cup vegetable oil (4 ounces); 1/3 cup apple butter; 1/2 cup all-purpose flour (65 grams); 1/2 cup brown sugar (105 grams); 1/2 cup walnuts (finely chopped); 4 tablespoons salted butter ((softened)); 1/2 cup powdered sugar; 2-4 tablespoons apple cider ((or heavy cream))