Peel onions, leaving root ends intact. Set onions on root end, and cut vertically at 1/4-inch intervals to within 1/2 inch of root end. Turn onions clockwise, and cut in same manner, making a crisscross pattern. (Onions will look like blossoms.)

Arrange onions in a 13- x 9-inch baking dish, allowing room in between for each to open. Drizzle with half of melted butter, and sprinkle with salt and pepper, if desired.

Bake at 350 for 30 minutes, basting occasionally with remaining butter.

Sprinkle with pecans, and bake 15 to 20 more minutes or until golden brown.