Combine the cornmeal with 3 cups of water in a medium saucepan over medium heat. Cook, stirring occasionally, for about 15 minutes, until the grits are tender and creamy. Stir the grated cheese into the grits, and season with salt and pepper. Cover to keep warm.

Heat the olive oil in a large skillet over medium-high heat. Add the sausage and cook 4-6 minutes, breaking up the sausage with the back of a spoon, until browned. Use a slotted spoon to transfer the sausage to a plate. Remove all but 2 tablespoons of fat from the skillet, and lower heat to medium. Add the white parts of the scallions, and cook for 1-2 minutes, until softened. Remove from heat and stir in the apple cider vinegar. Place the torn collard greens in a large bowl, and pour the warm dressing on top. Toss the greens to coat in dressing, and use your hands to massage the collards until they wilt, 2-3 minutes.  Sprinkle with salt and pepper. Add the green parts of the scallions and toss to incorporate. 

Serve the grits topped with the collards and sausage.