Preheat the oven to 180C (160C fan) / 350F. Grease a 23cm / 9 inch cake tin and line the bottom with non-stick baking paper.
In a large mixing bowl, whisk together all the wet ingredients. Taste test and add a touch more almond extract, if desired.
In a separate bowl, mix together all the dry ingredients except the ground almonds.
Slice the pears ready for the topping. To do this, I slice the pears into halves, then quarters. Using a sharp knife, scoop out the core. Place the pears cut side down on a chopping board, and slice into even-sized thin slices.
Sift the dry ingredients into the wet ingredient bowl and stir through to combine (but do not overmix). Add the ground almonds and stir through.
Tip the batter into the prepared tin and use a silicone spatula to distribute it evenly. Arrange the pear slices on top, then add a light sprinkle of ground cinnamon.
Place on the centre rack in the oven and bake for 50-55 minutes, or until a skewer inserted through the middle comes out clean.
While the cake is cooling, prepare the glaze. In a small bowl, mix 1 TBSP water with the cornflour until dissolved. Add the remaining water, sugar and vanilla extract to a small pan over medium heat. Once the sugar has dissolved, whisk in the cornflour paste. Gently bring to the boil, whisking continuously. When the mixture has thickened slightly remove from the heat.
Use a silicone pastry brush to lightly coat the top in the glaze (you won’t need to use all the glaze). Leave the cake in the tin until it has completely cooled (it will firm up as it cools), then transfer to an airtight container. The cake will keep for 5 days in the refrigerator. It also freezes well.