Preheat the oven to 350°F and grease a bundt pan with baking spray.
In a bowl, combine diced pears with 1/2 cup granulated sugar and cinnamon. Mix well and set aside.
In a medium bowl, whisk together flour, 1 1/2 cups sugar, baking powder, and salt.
In a large bowl, whisk eggs, oil, milk, and vanilla extract until smooth. Gradually add the dry ingredients and mix until fully incorporated.
Pour one-third of the batter into the prepared pan. Add half of the pear mixture. Repeat layering, ending with batter on top.
Bake for about 1 hour 20 minutes or until a toothpick inserted comes out clean.
Cool the cake in the pan for 20 minutes, then invert onto a plate and remove the pan.
For the caramel sauce, melt brown sugar in a skillet over low heat. Add butter and stir until combined. Stir in heavy cream and cook for a few minutes. Remove from heat and add vanilla. Let cool for 15 minutes to thicken.
Drizzle caramel sauce over the cooled cake, slice, and serve.
Notes
Use ripe but firm pears for best texture.
Ensure all refrigerated ingredients are at room temperature for a smoother batter.
Store leftovers covered at room temperature for up to 2 days or refrigerate for up to 5 days.
The caramel sauce can be made ahead and reheated gently before serving.