Preheat oven to 350℉. Grease and flour a 9-inch round cake pan.
Combine all dry ingredients together in a large bowl. Whisk together until ingredients are well incorporated. Set aside.
In a mixer bowl add butter and sugar. Cream for two minutes until fluffy.
Gradually add egg and vanilla until combined.
Gradually add yogurt and milk until combined.
Slowly add the flour mixture to wet mixture. Mix until just combined. Do not overmix.
Using a spatula, gently fold pears into the batter until they are spread throughout.
Pour prepared batter into the cake pan, evenly spread out and set aside.
Topping: combine brown sugar, cinnamon and pecans.
Spread the topping evenly over the cake batter.
Bake in middle rack for 40-50 minutes or until the toothpick has a few moist crumbs on it.
Cool on a rack for a few minutes before you serve.