How to Make It
Preheat the oven to 425°. Put the sweet potatoes on a baking sheet and roast for 50 minutes, or until tender when pierced. Remove from the oven and let cool slightly. Reduce the oven temperature to 375°.
Halve the sweet potatoes lengthwise and scrape the flesh into a medium bowl; discard the skins. Mash the sweet potatoes until smooth. Stir in the cottage cheese, chives, garlic, lemon juice, olive oil and vinegar and season with salt and pepper.
Toast the bread on a baking sheet for 10 minutes, or until crisp. Top each slice with the sweet potato mixture and serve.