Heat the oven to 190 C / 375 F.
Halve and core the pears using a melon baller or small spoon, and arrange cut side up in a baking dish.
Whisk together melted butter, maple syrup, cinnamon, lemon juice, vanilla, and salt in a small bowl.
Pour the maple mixture evenly over the pear halves, making sure some pools in each cavity.
Bake for 15 minutes, then remove and baste the pears with the pan juices using a spoon or brush.
Return to the oven and bake another 10 to 15 minutes, until a fork slides into the thickest part with no resistance and the edges look caramelized.
While the pears finish baking, toast the pecans in a dry skillet over medium heat for 2 to 3 minutes, until fragrant.
Remove pears from the oven, scatter toasted pecans over the top, and spoon extra pan juices over each half before serving.