Pat beef dry with paper towels, trim, and cut into 1 1/2- to 2-inch pieces. Place in a bowl with 2 tablespoons cornstarch, salt, and pepper; toss to coat beef evenly.

Heat oil in a large nonstick skillet over medium-high heat. Add half of the beef and cook, turning often, until beef is browned on all sides, about 6 minutes (do not overcrowd the skillet to ensure browning). Repeat process with remaining beef, using any residual oil in the skillet. (Do not wipe skillet clean.) Place browned beef in an ungreased 6-quart slow cooker.

Lower heat to medium and add curry paste to skillet, stirring to release any browned bits. Add beef broth and coconut cream; stir to combine. Pour mixture over beef in slow cooker. Add potatoes to slow cooker; cover and cook on HIGH for 4 hours, or LOW for 6 hours, until beef is tender.

Remove beef and potatoes from the slow cooker. Pour the cooking liquid into a bowl or measuring cup, skim off fat, and discard.

Pour liquid into a saucepan and bring to a boil. Whisk together remaining cornstarch and water, add to saucepan, and cook until thickened (2-5 minutes).

Add beef, potatoes, lime zest, and juice back into the thickened sauce. Stir well.