Place the hazelnuts in a dry skillet and cook over medium heat for 4 minutes, or until fragrant. Be sure to stir the nuts frequently to prevent burning. Set aside.
Preheat the oven to 400ºF. Spread the butter in the bottom of a 13-inch x 9-inch x 2-inch baking dish. Sprinkle with 2 tablespoons of sugar. Place the pear halves cut side down in the prepared baking dish. Bake for 35 to 40 minutes, or until the pears are tender when pierced with the tip of a knife.
Meanwhile, place the remaining sugar in a small saucepan. Cook over medium-high heat, swirling the pan frequently, for 5 minutes, until the sugar melts and turns amber in color. Remove the pan from the heat and slowly pour in the orange juice to avoid sputtering hot liquid. Return the pan to medium-low heat. Cook the sauce, stirring constantly, for 5 minutes, until the sauce thickens slightly. Stir in the figs and liqueur, if using. Set the sauce aside.
Remove the pears from the baking dish and place on serving plates. Add any juices remaining in the baking dish to the sauce.
Serve the pears warm or at room temperature. Spoon the sauce over the pears and sprinkle with the hazelnuts. If the sauce thickens after sitting, rewarm it over low heat.
Tip: The mellow sweetness of pears and the zesty tang of orange are paired perfectly in this elegant dessert.