In a large bowl, whisk together the gluten free flour blend, light brown sugar, cinnamon and xanthan gum.

Add the cubed cold butter and rub it into the dry ingredients with your fingertips until you get a crumbly mixture that forms clumps when you press it together. You want a mixture of small “crumbs” and larger pea-sized pieces.

Set aside until needed.

Adjust the oven rack to the middle position, pre-heat the oven to 375ºF (190ºC) and line 10 holes of a 12-hole muffin pan with paper liners.

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

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

Add the dry ingredients and the chopped apples to the wet ingredients, and use a rubber spatula or a wooden spoon to mix everything together into a fairly thick batter. Make sure that there are no flour clumps and that the apple chunks are evenly distributed throughout the batter.Tip: As you fold everything together, the apples first get coated in the dry ingredients and then mixed into the batter. This essentially mimics the step you often see in recipes which calls for coating fruit (such as berries or chopped apples) in flour, but here this happens in situ.

Use an ice cream/cookie scoop or a spoon to divide the batter evenly between the 10 muffin liners, filling each to the brim.Tip: For beautifully domed, bakery-style muffins, it’s important that you fill the muffin liners VERY generously, they need to be filled to the brim or even dome slightly above the edge of the liners (because the batter is very thick, it won’t overflow).

Sprinkle the top of each muffin generously with the streusel topping – you shouldn't have any streusel left over at the end.

Bake at 375ºF (190ºC) for about 20-24 minutes or until the muffins are well risen, golden brown on top and an inserted toothpick or cake tester comes out clean.

Allow the muffins to cool in the muffin pan for about 5-10 minutes, then transfer them out of the pan and onto a wire rack to cool. Serve warm or at room temperature.

The gluten free apple crumble muffins keep well in a closed container in a cool dry place for about 2-3 days.