For the cinnamon sugar, mix everything that is listed under 'For the cinnamon sugar' until combined and keep it aside until further use.
Pre-heat an oven at 180°C. Grease and line the bottom and the sides of the cake tin with butter and parchment paper.
Sift together flour, salt and baking powder and keep it aside.
Add butter and sugar in a mixing bowl and beat until smooth.
Add egg, one at a time and beat until just combined.
Add the milk and beat it along with the butter mixture.
Add vanilla extract and mix well.
Add sifted flour mixture and beat it until just combined and lump-free.
Peel and chop one pear very finely and add it to batter and fold gently.
Peel and slice the rest of the pears into thin pieces.
Pour the batter into the prepared tin. Gently tap against the table to remove any air bubbles.
Arrange the sliced pears over the batter, starting from the outside edge. Sprinkle with the cinnamon sugar on top. Bake in a pre-heated oven for 30-45 minutes or until a skewer inserted comes out clean.
Cool the cake for 10 minutes in the tin, then remove it from the tin, slice and serve warm.