Preheat the oven to 375°F (190°C). Butter a 2-quart baking dish.
Combine the sliced pears, brown sugar, cornstarch, and cinnamon in the baking dish or in a separate bowl. Set aside.
To make the topping:
Place the butter in a medium saucepan. Cook over medium heat, stirring frequently. Once the butter melts and begins to foam, continue cooking until brown specks begin to form beneath the foam and the butter has a nutty aroma. Remove from the heat and set aside to cool slightly.
In a separate bowl, combine the oats, brown sugar, flour, cinnamon, ginger, nutmeg, and salt.
Add the browned butter, and mix just until the ingredients are moistened and crumbs have formed. Sprinkle the topping over the filling.
Bake 40 to 45 minutes, or until the topping is golden brown and the filling is bubbly.
Cool in the pan on a wire rack.
Notes
Store leftovers in an airtight container at room temperature up to 2 days, in the refrigerator up to 4 days, or in the freezer up to 3 months.