Grease a 9-inch spring form pan and pre-heat the oven to 350˚F.
In a large bowl mix the flours, baking powder, baking soda, salt, sugar.
In a small bowl or jug, whisk together the sour cream/yogurt, milk, vanilla, oil, flax meal and water.
Make a well in the centre of the dry mix and pour in the wet mixture. Fold everything together until evenly mixed. Scrape the batter into the prepared pan and gently tap the pan on the counter to level out the batter.
Lay the fruit slices on the top of the batter in a neat pattern.
In a small bowl mix together the sugars, flour, cinnamon, salt and chopped nuts for the topping. Slowly drizzle, a tablespoon at a time, the oil into the dry mixture. Mix with a fork until the mixture resembles wet sand. Sprinkle the topping all over the top of the cake.
Bake in the centre of the oven for 70 to 80 minutes. Insert a wooden skewer into the centre of the cake to make sure it’s cooked through.
Once cooked fully, remove from the oven and allow to cool in the pan for 45 minutes. Then transfer to a wire rack to cool fully.