Preheat the oven to gas 4 / 180C / 350°F and grease & flour a standard 9 x 5 loaf tin
Mix the brown sugar and cinnamon together and set aside
Cream the granulated sugar and sunflower spread together until light and fluffy, then mix in the vanilla extract
Add in the milk and apple puree then sift in the flour, baking soda and xanthan gum if using together, stirring into the creamed mixture until just combined
Gluten free flour is thirsty so add more milk if you need it, the consistency should be thick like a banana bread batter
Pour half of the batter into the loaf tin and spoon a line of the cinnamon sugar down the centre
Use the end of the spoon or a clean finger to gently swirl the cinnamon mixture around a little
Now evenly spread half of the diced apple on top and pat in slightly
Pour the rest of the batter on top of the apple layer
Repeat the cinnamon sugar line and swirl it, then gently pat the last of the apple into the top of the cake. Save a pinch of the cinnamon mixture for sprinkling over the very top
Bake for 70 minutes, the top should be caramelized and the cake pulled in from the edges of the tin
Let stand in the tin for 10 minutes for the outside to set enough to be able to release, then run a sharp knife around the edge and remove from the tin
Serve immediately with hot custard poured over, it will be slightly gooey in the middle
https://cookpad.com/us/recipes/332987-vickys-vanilla-custard-gluten-dairy-egg-soy-nut-free
