Preheat the oven to 350°F. Position the oven rack in the bottom third of the oven. Line a 9 x 5 inch loaf pan with parchment paper, letting the sides overhang to use as "handles" to easily pull the baked loaf out later.
Whisk the dry ingredients in a medium mixing bowl: flour, cornstarch, baking powder, baking soda, pumpkin pie spice cinnamon, and salt.
In a large mixing bowl, whisk together the wet ingredients: sugars, pumpkin, coconut milk, and vanilla.
Stir the dry into the wet until just combined. Ensure there is no white flour visible, but do not over mix, a few lumps are okay.
Stir in the diced pear, if using.
Pour the batter into the prepared loaf pan using a spatula to scrape it all out of the bowl. Smooth out the top of the batter.
Bake in the preheated oven for 45 minutes. Add a piece of aluminum foil tented over the top of the loaf and bake an additional 15 to 25 minutes until a knife or toothpick inserted into the middle comes out clean. A few crumbs are okay, but it shouldn't be gooey.
Let the bread cool in the pan on a cooling rack for 10 minutes. Then, using the "handles" of the parchment paper, gently lift the bread out of the pan and let it cool on the cooling rack for at least an hour. (If the bread is stuck to the sides of the pan in some parts, gently run a knife along the side of the pan to release it.)
Once the bread is cooled, slice the loaf using a serrated knife.