Preheat the oven to 160C / 320F. Grease three 20cm round cake pans and line the base and side with baking parchment.
Sift the flour, cinnamon and nutmeg into a large bowl. In a separate bowl, beat your butter and maple sugar either using an electric whisk (or in a stand mixer fitted with paddle attachment) until creamy and pale. Add the eggs, one at a time, beating well after each addition.
Add the vanilla bean paste, and reduce your speed to low before incorporating the flour mixture, buttermilk, a pinch of salt flakes and the grated apple. Fold to combine.
Divide the mixture between your prepared cake tins and smooth tops with a palette knife or spatula. Bake for 1 hour 30 minutes, or until a skewer inserted in the centre of a cake comes out clean. Remove from the oven and set aside to cool completely in pans.
Meanwhile, make the filling by beating the butter until smooth. Add the maple sugar and vanilla bean paste and beat again until the filling starts to come together. Grate in the nutmeg and add the cream cheese, straight from the fridge. Fold in with a spatula to avoid your filling turning liquidy. N.B. Be careful not to overbeat as this will result in a runny frosting! To make the maple apple caramel, place the apple juice and maple syrup in a deep saucepan over medium heat and simmer for 10 minutes, swirling occasionally, until reduced by one-third. Set aside to cool completely.
Now make your toffee apples (following the safety instructions detailed in this post). Line two heat-proof trays with baking parchment, and set a wire rack over the top of one of the trays. Pour your maple sugar into a deep non-stick saucepan over medium-low heat and cook, without touching, until you begin to see it turning to a golden liquid. Once a liquid begins to form, swirl the pan occasionally, for 7-9 minutes or until you have a golden brown caramel and maple sugar has completely dissolved.
Using metal tongs, dip each apple into the caramel, one at a time, until completely coated then place on a wire rack to set. Pour any remaining caramel over parts of the apples you might have missed, and then the rest on the second prepared baking tray. Scatter with the roasted almonds. Set aside to cool completely, then break into shards and place in a food processor to finely crush.
Trim the tops of each cake so you have a flat surface to work with and place the first layer on a serving plate. Spread one-third of the filling over the top of the cake and scatter with half of the praline. Sandwich the second cake and top with one-third cream cheese mixture, repeating the process with the remaining praline. Use a palette knife to ice the sides of the cake lightly with remaining one-third filling so you have a ‘naked’ look to your cake.
Arrange the crunchy toffee apples on top of your cake, drizzle with the apple-maple glaze and sprinkle with rose petals.