Creating Apple Crumb Cake with Cinnamon Apple Drizzle is simple if you follow these steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan.
2. Mix Dry Ingredients: In a large bowl, combine the flour, granulated sugar, baking powder, baking soda, and salt.
3. Cream Butter and Sugar: In another bowl, cream the softened butter with the remaining sugar until light and fluffy.
4. Add Eggs and Vanilla: Beat in the eggs one at a time, followed by the vanilla extract.
5. Combine Wet and Dry Mixtures: Gradually add the dry ingredient mixture to the butter mixture, alternating with the buttermilk until just combined.
6. Fold in Apples: Gently fold in the diced apples until they are evenly distributed throughout the batter.
7. Prepare the Crumb Topping: In a medium bowl, mix together the flour, brown sugar, rolled oats, cinnamon, and melted butter until crumbly.
8. Pour Batter into Pan: Spread the batter evenly into the prepared baking pan.
9. Add Crumb Topping: Sprinkle the crumb topping evenly over the batter.
10. Bake: Place in the preheated oven and bake for 40-45 minutes, or until a toothpick inserted in the center comes out clean.
11. Cool: Remove from the oven and let it cool in the pan for about 15-20 minutes.
12. Make the Drizzle: In a small bowl, whisk together the powdered sugar, milk, cinnamon, and apple cider until smooth.
13. Drizzle Over Cake: Once the cake has cooled slightly, drizzle the cinnamon apple mixture over the top.