Pierce the skin of the potatoes several times to allow the steam to escape.
Bake on the oven rack for 1 hour or until tender. Let the potatoes stand until cool enough to handle.
Meanwhile, in an 8-inch skillet, heat the olive oil over medium-high heat. Cook and stir the onion and garlic for 3 to 4 minutes or until the onion is tender. Stir in the sage, salt and pepper.
Place the cottage cheese and onion mixture in the bowl of a food processor; blend until almost smooth, scraping the sides as needed.
Cut off the top 1/3 of each potato. Using a spoon, scoop the flesh into the processor bowl, being careful not to tear the potato skins; discard the potato tops. Pulse the cottage cheese and potato mixture several times until blended.
Spoon the potato mixture back into the skins. Place the filled potatoes in a baking dish. (The potatoes can be covered and refrigerated at this point for up to 24 hours.) Reduce the oven to 350 degrees. Sprinkle the pecans over the tops of the potatoes. Bake uncovered 25 to 35 minutes or until the pecans are toasted and the potatoes are hot. (If the filled potatoes were refrigerated, remove from the refrigerator 30 minutes topping with pecans; top and bake as directed.) Tip: To keep the oven clean, place an oven rack below the rack on which sweet potatoes are baking. Place a sheet of aluminum foil below the potatoes to catch any drips from the potatoes as they bake.