First things first, let's get that oven preheated to 350°F (175°C). While it’s warming up, grab your 9-inch cake pan and give it a good grease and flour. This ensures your beautiful cake doesn't stick.

In a big ol' bowl, whisk together all your dry ingredients: flour, granulated sugar, baking powder, cinnamon, salt, and baking soda. Give it a good mix so everything is nicely combined.

Now, add your softened butter to the dry ingredients. You can use a pastry blender, or just your fingertips (my personal favorite!), to cut the butter into the flour mixture until it looks like coarse crumbs. Think pea-sized pieces.

In a separate bowl, whisk together your wet ingredients: the eggs, buttermilk, and vanilla extract.

Pour those lovely wet ingredients into the dry ingredients. Mix everything together until it's just combined. It’s super important not to overmix here – we want a tender cake, not a tough one! A few streaks of flour are okay.

In a medium bowl, mix together the brown sugar, 1 teaspoon of your cinnamon, and the teaspoon of flour.

Now, peel, core, and chop your apples into nice bite-sized pieces. No need to be super precise here, rustic is good!

Add those chopped apples into the brown sugar and cinnamon mixture. Toss them gently to coat each apple piece. This is going to create that yummy, spiced apple layer in the middle.

Pour about half of your cake batter into the prepared cake pan. Spread it out evenly.

Next, carefully spoon that glorious apple mixture right over the batter. Try to get an even layer.

Gently spoon the remaining cake batter over the apple layer. Be a bit careful not to disturb the apples too much.

Now for the magic topping! Sprinkle the remaining 1 teaspoon of cinnamon and the 2 tablespoons of granulated sugar all over the top of the cake. This will create that irresistible crunchy, caramelized crust as it bakes.

Bake for about 40-50 minutes. You’ll know it’s ready when a wooden skewer (or a toothpick) inserted into the center comes out clean.

Once it’s out of the oven, let the cake cool in the pan for about 10 minutes. This helps it set up. Then, carefully invert it onto a wire rack to cool completely.

In a small bowl, whisk together the powdered sugar and your milk, apple cider, or apple juice until it’s smooth and pourable. If it’s too thick, just add a little more liquid, about a teaspoon at a time, until you get that perfect drizzling consistency.

Once your cake has cooled, drizzle that beautiful glaze all over the top. Let it set for a few minutes, and then slice yourself a piece!