Place potatoes, cut sides down, in an 11 x 7-inch microwave-safe baking dish. Add 1/4 cup water; cover with plastic wrap. Microwave at HIGH 15 minutes or until potatoes are tender. Cool slightly; discard potato skins.

Heat a saucepan over medium-high heat. Add oil; swirl to coat. Add onion; sauté 1 minute or until translucent. Stir in cumin and red pepper. Add stock to pan; bring to a boil. Place half of sweet potato and half of stock mixture in a blender. Remove center piece of blender lid (to allow steam to escape); secure blender lid on blender. Place a clean towel over opening in blender lid (to avoid splatters); blend until smooth. Pour pureed soup into a large bowl. Repeat procedure with remaining sweet potato and stock mixture. Stir in salt. Divide soup evenly among 6 bowls; sprinkle cooked bacon and Parmesan cheese evenly over top. Garnish with parsley, if desired.