Make the apple filling first, so it has time to cool down. The filling needs to be lukewarm or at room temperature when you assemble the cake.

In a large saucepan over medium-high heat, melt the butter. Add the chopped apples, light brown sugar, lemon juice and cinnamon, and stir to combine.

Cover with a lid and cook covered over medium-high heat for about 5-6 minutes or until the apples are tender (so that a fork easily passes through them) and they've released their juices.

Remove the pan from the heat. In a small bowl, mix together the cornstarch (US)/cornflour (UK) and water to create a cornstarch slurry.

Pour the apple filling into a bowl or deep plate, and set aside to cool. It needs to be lukewarm or cooled completely to room temperature before you start assembling the cake.

Adjust the oven rack to the middle position, pre-heat the oven to 350ºF (180ºC) and line a 9-inch (23cm) square baking pan with parchment/baking paper.Tip: When lining the baking pan, I recommend leaving some parchment/baking paper overhang, as that will help with removing the cake from the pan later on.

In a large bowl, whisk together the light brown sugar, melted butter, oil, eggs, yoghurt and vanilla until well combined and smooth.

In a separate bowl, whisk together the gluten free flour blend, almond flour, cinnamon, baking powder, baking soda, xanthan gum and salt.

Add the dry ingredients to the wet and mix well until you get a smooth, fairly loose cake batter with no flour clumps.

As you're assembling the cake, make sure to reserve about 1 tablespoon of the thickened apple juices to use in the glaze.

Transfer half of the cinnamon cake batter into the lined baking pan and smooth it out into an even layer.

Spoon about ⅔ of the apple filling over the batter, making sure you get a fairly even distribution. (See blog post for photos.)

Dollop the remaining cake batter on top and spread it out into an even layer – be gentle, you don’t want to displace the underlying apple filling too much (nor mix it into the cake batter).

Spoon over the remaining apple filling, dotting it evenly on top of the cake batter. Use a skewer or the end of a knife to gently swirl the apple filling into the top of the cake batter – don’t reach all the way to the bottom of the pan, you just want to swirl around the top ¼ inch (5-6mm) or so.

Bake the cake at 350ºF (180ºC) for about 40-45 minutes or until it's deep golden brown on top and an inserted toothpick or cake tester comes out clean.

Allow the cake to cool in the baking pan for about 15 minutes while you prepare the glaze.

In a bowl, whisk together the powdered/icing sugar, milk, vanilla and the reserved thickened apple juices.You can adjust the glaze consistency as needed, by adding more powdered/icing sugar (to make it thicker) or more milk (to make it runnier). You want the glaze to be fairly runny, so it'll flood all the nooks and crannies.

Pour the glaze over the warm cake and use the back of a spoon to spread it around, so it settles into all the nooks and crannies and creates a fairly even layer on top of the cake.You don't have to use up all of the glaze – if you prefer a slightly less sweet dessert, you can use only ¾ of it.

Allow the glaze to dry and set into a crisp, crackly consistency before slicing and serving. You can enjoy the cake either warm or cooled completely to room temperature.

The gluten free apple fritter cake is at its best on the day of baking. But it stores well in a loosely covered container in a cool dry place for about 2-3 days, just note that the glaze may soften with time, as it absorbs some of the moisture from the cake (and also some of the ambient moisture).