Preheat oven to 350 degrees F.
Scrub Jerusalem artichoke tubers and cut out eyes. Cut tubers into 1" pieces.
Mix olive oil, thyme, garlic and sea salt together in a large bowl; add Jerusalem artichoke pieces and toss to coat. Arrange coated pieces in one evenly spaced layer on a baking sheet.
Roast for 35-45 minutes or till tender.