Preheat the oven to 180C(Fan)/350F/Gas Mark 4 and line the bottom of your cake tin with baking paper.
Put flour, baking powder, baking soda, cinnamon, ground ginger (if using) and sugar in a large bowl and mix gently with a whisk. Alternatively, sieve all the dry ingredients (with the exception of sugar) into a large bowl, add sugar and give it all a quick mix to incorporate.
Peel and finely grate fresh ginger.
Peel, core and quarter or slice the pears (depending on the size).
In another bowl mix together vegan yogurt, soya milk, vinegar, oil and grated ginger until incorporated.
Make a well in the middle of your dry ingredients and pour in the wet mixture. Fold in gently until fully incorporated but don't overmix.
Pour cake batter into prepared cake tin.
Arrange sliced pears gently on top of the cake batter, pushing them in ever so slightly.
Sprinkle over some demerara sugar and bake in the preheated oven for 40-45 minutes or until skewer inserted into centre comes out clean.
Take the cake out of the oven and let it cool slightly in the tin before taking it out onto the cooling rack to cool completely.
Enjoy on its own or with a scoop of vegan vanilla ice cream!