To cut round vegetables into chunks for stewing, roasting or braising, cut the vegetable in half lengthwise and lay the flat side on the board. Cut into thick wedges; gather the wedges and cut crosswise to create the size chunk you want.
For long vegetables, trim the ends and lay the vegetable on the board, holding onto the thicker end. With your knife at an angle, cut crosswise, taking a chunk off the end. Roll the vegetable 90 degrees and cut again. Keep rolling and cutting until you have cut the entire vegetable, adjusting the degree of rolling so that the pieces are similar in size when you are through.