Halve pears lengthwise and core. Cut pears lengthwise into 1/4-inch-thick slices and sprinkle on both sides with pepper.
In a large non-stick skillet heat 1 tablespoon butter over moderately high heat until foam subsides and sauté half of pear slices on both sides until golden brown, about 3 minutes total. With a spatula transfer sautéed pears to a plate and drizzle with half of lemon juice. Sauté and drizzle with remaining pear slices in same manner.
Divide pears among 4 plates. Sprinkle pears with blue cheese and serve with fried sage leaves.
