For Crumble Topping

Mix flour, sugar, cinnamon, and salt in a bowl. Add the melted butter and stir with a fork until the mixture becomes clumpy and no dry flour remains. Place the bowl in the freezer while you prepare the cake so the topping bakes up extra crisp.

For Cinnamon Cake

Peel and cut the apples into ½-inch cubes, then toss them with sugar and cinnamon until evenly coated. Set them aside so they can release a little juice and develop more flavor.

Preheat the oven to 350°F (175°C) and line an 8-inch (20 cm) springform pan with parchment paper. In one bowl, whisk together the yogurt, sugar, vanilla extract, and melted butter until smooth.

In another bowl, combine the flour, baking powder, baking soda, cinnamon, and salt. Gently mix the dry mixture into the wet mixture until just combined. The batter will be thick, which helps hold the apple filling in place.

Spread half of the batter evenly into the prepared pan, then layer all of the cinnamon apples on top, don't use excess liquid released from apples. Spoon the remaining batter over the apples and gently spread in an even layer to cover. Sprinkle all of the chilled crumble topping generously over the surface.

Bake the cake for 40–50 minutes, or until the top is golden brown and a toothpick inserted in the center comes out mostly clean. Let the cake cool completely on a wire rack before adding the icing.

For the Maple Icing

To make the maple icing, whisk powdered sugar with maple syrup (or honey/agave) until smooth and pourable. Drizzle over the cooled cake for a sweet, bakery-style finish.

Store your apple crumble cake in an airtight container in the refrigerator for up to 3 days, or freeze for up to 2 months. Serve plain, dusted with powdered sugar, or with a scoop of vanilla ice cream for the ultimate autumn dessert.