Pre-heat your oven to 170℃/340℉ (fan-forced). Grease and line a spring form pan/ tin with baking paper. I used a 22cm cake tin.
In a mixing bowl or food processor, beat the butter, yoghurt, sweetener of your choice, eggs, zest and ginger until well combined.
Add the baking powder, bicarbonate of soda and sea salt and blend again for a few seconds to just combine.
Now gently fold in the spelt flour and mix until the flour is just combined. The more you mix this, the heavier the cake will become, so less is certainly best.
Pour the batter into the prepared cake tin, top with the pear, sprinkle over the sugar and bake for 40 minutes or until the cake is firm in the middle (a skewer inserted into the middle will come out clean).