6 semi-firm Bosc pears (2 pounds)
1 tablespoon butter
1⁄4 cup fresh lemon juice
1 tablespoon balsamic vinegar
3⁄4 cup sugar
4 mint leaves (optional garnish)
Preheat oven to 375° F. Peel pears but do not remove their stems. Using a melon baller or citrus spoon, hollow out the core and seeds from the bottom of each pear. Place butter in an 8-by-8-inch glass or ceramic casserole dish and put in oven for 1-2 minutes, until butter just melts.
Remove from oven and whisk in lemon juice, balsamic vinegar and sugar. Roll pears in lemon-sugar liquid to coat them. Stand pears upright in dish and loosely tent with aluminum foil. Place in oven and roast for 30 minutes. Remove foil and allow to cook uncovered for 1 more hour until golden and tender, occasionally basting with juices. Allow to cool to room temperature.
To serve, drizzle 1 tablespoon of caramelized cooking liquid over each pear. If desired, garnish with mint by making a tiny cup in the pear and inserting the leaf.