Step 1

Combine potatoes, water, and salt in large saucepan. Cover and cook over medium-low heat, stirring occasionally, until paring knife inserted into potatoes meets no resistance, about 20 minutes.

Step 2

Remove from heat. Using potato masher, mash potatoes until mostly smooth with some small chunks remaining. Let cool until no longer hot to touch, about 30 minutes. (Mashed sweet potatoes can be transferred to bowl, covered with plastic wrap, and refrigerated for up to 2 days.)

Step 3

Set wire rack in rimmed baking sheet and line half of rack with triple layer of paper towels. Stir cheddar, flour, eggs, scallions, cilantro, chipotle, cumin, and pepper into potato mixture until fully combined.

Step 4

Heat oil in 12-inch nonstick skillet over medium heat to 350 degrees (to take temperature, tilt skillet so oil pools on 1 side). Using greased ¼-cup dry measuring cup, place 6 portions of potato mixture in skillet. Press portions into approximate 3-inch disks with back of spoon.

Step 5

Cook fritters until deep brown, 2 to 3 minutes per side, using 2 spatulas to carefully flip. Transfer fritters to paper towel–lined side of prepared rack to drain for 15 seconds on each side, then move to unlined side of rack. Return oil to 350 degrees and repeat with remaining potato mixture. Serve with sour cream and lemon wedges.