Preheat oven to 425 degrees.
Peel, core and cut pears into 1 /2 inch-thick slices.
Toss the pear slices with lemon juice in a large bowl; add sugar and toss once again.
Transfer to a baking pan large enough to hold the slices in a single layer.
Roast, stirring occasionally to prevent scorching, until the pears are tender and golden brown, 25 to 30 minutes.