Preheat oven to 375°F (190°C). Set aside an 8x8 square baking pan or a medium-sized gratin dish.
In a large mixing bowl, toss the pears in the lemon juice. In a small mixing bowl, whisk together the sugar, cornstarch, cinnamon, and cardamom. Sprinkle over the pears and toss to coat. Pour into the baking dish.
In a medium-sized mixing bowl, whisk together the flour, oats, brown sugar, salt, baking soda, baking powder, and cinnamon; set aside.
In a small saucepan set over medium heat, add the 4 tablespoons of butter. Heat until the butter foams, then begins to brown and become speckled (about 3-5 minutes), whisking every so often. Pour into the bowl with the topping ingredients and mix until crumbles form. Sprinkle over the filling.
Place in the oven and bake for 35-45 minutes, or until pears are tender and topping is golden brown. Remove from the oven and allow to cool for 20 minutes. Serve warm.
Notes
*You can also use melted butter instead of browned butter.-You can toss in 2/3 cup of fresh cranberries to the filling; just increase the granulated sugar to 1/3 cup.-You can add 1/4 cup of your favorite finely chopped nuts to the topping.To STORE Browned Butter Pear Crisp, cover it tightly and refrigerate for up to 3-4 days. You can FREEZE it for up to 2 months by wrapping it well in plastic wrap and foil.REHEAT the crisp in the oven at 350°F (175°C) for 15-20 minutes until warmed through, or microwave individual servings for 1-2 minutes. For best results, enjoy it fresh from the oven or reheated, paired with a scoop of vanilla ice cream.