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.

In a large bowl, combine the light brown sugar, softened butter and vanilla, and mix well with a wooden spoon or rubber spatula until combined.

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

Add the dry ingredients to the butter-sugar mixture and mix well until it starts clumping together. Then, give it a knead until you get a homogeneous cookie dough. Set aside until needed.

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

In a separate bowl, whisk together the gluten free flour blend, almond flour, baking powder, baking soda, xanthan gum and salt, and add them to the wet ingredients.

Whisk well until you get a smooth cake batter with no flour clumps.

Add the sliced peaches, sugar, cornstarch and cinnamon to a large bowl and toss to combine.

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

Spoon the peach slices evenly over the cake batter.

Crumble the streusel topping over the peach layer, making sure that you get a fairly even coverage.

Bake at 350ºF (180ºC) for about 40-45 minutes or until the crumble topping is evenly golden brown and an inserted toothpick/cake tester comes out clean.

Allow the cake to cool until warm before you remove it from the baking pan.

Serve warm or cooled completely to room temperature. If you wish, you can dust the top with some powdered/icing sugar before slicing and serving.