In an electric mixer bowl, whip up the sugar and butter until well combined for about 1 minute.
Add in the vanilla, lemon zest and eggs. Continue mixing on high speed for 1-2 minutes until they are well combined.
Add in the baking powder, sifted flour and a pinch of salt. Mix again for about 1 minute. Gradually add ½ cup of milk and ⅓ cup oil while mixing on low speed. Mix for another minute or two on low speed.
Line the bottom of the pan with parchment paper and grease or spray a round spring foam baking pan then pour the batter in. Ideally, a 10 x 3 inch deep pan is the best size.
After placing the batter in your pan, spread a layer of the sliced pears to cover the whole batter. Sprinkle some cinnamon and the brown sugar on top of the pears.
Bake in a pre-heated 350 F oven for 40 minutes then lay over an aluminum foil wrap on top to cover the cake and bake for another 10-15 minutes depending on your oven. Insert a wooden skewer to make sure it's completely clean before removing the cake. It may take less or a bit more time depending on your oven.
Remove the cake from the oven and cover with a kitchen towel to let it cool down. It may take up to 1 hour to completely cool down. Dust with some confectioner sugar right before serving.
Always use room temperature softened butter.
If you are not serving right away, I recommend not dusting the cake right away. The moisture of the pears will absorb the sugar. Dust the cake right before serving.
Only use real butter. No fake butters.
Do not use a smaller pan other than what is recommended, which is 10 x 3" round spring foam pan (easy release pan).
Do not use under ripe pears. Always use soft pears, but not mushy pears
Depending on your oven and thickness of the pan, the cake might take less or more time. Insert a tooth pick or skewer into the center of the cake to check if it comes out clean.
You may add nuts or raisins right before the pear before baking, if you like. Just dust them with a little bit of AP flour before doing that.