While your sous vide machine heats, prepare the corn by ensuring it's completely shucked and all silk has been removed—I like to run my fingers under cool water over the corn to catch any remaining strands. Pat the ears dry with paper towels so they seal properly in the bag. In a small bowl, combine the kosher salt, granulated sugar, and freshly ground black pepper together.

Set your sous vide machine to 183°F and allow the water bath to reach temperature—this typically takes 10-15 minutes depending on your machine and water volume. While the water heats, divide the unsalted butter into four equal portions (about 3/4 tablespoon each) and place one portion with one sprig of fresh rosemary in a vacuum-seal bag or zip-lock freezer bag. Add one ear of corn to the bag, then sprinkle with one-quarter of the seasoning mixture from Step 1.

Seal the bag using either a vacuum sealer or the water-displacement method (submerge the bag in water, leaving the top edge unsealed, then seal once water pressure removes excess air). Repeat with the remaining three ears of corn, butter, rosemary, and seasoning in separate bags. Once your water bath reaches 183°F, carefully place all four bags into the water, ensuring they're fully submerged and not touching the heating element. Cook for exactly 30 minutes—this timing perfectly tenderizes the corn while maintaining its sweet flavor and slight bite.

After 30 minutes, carefully remove the bags from the hot water bath using tongs and place them on a clean surface. Open each bag and transfer the corn to a serving plate or directly to individual plates. Pour any butter and seasonings from the bag over each ear of corn for maximum flavor—I always make sure not to waste those infused juices, as that's where much of the delicious rosemary flavor lives.