Prepare a 9-inch square pan: line with foil and use an additional teaspoon of soft butter to 'grease' thoroughly.
Combine molasses, butter and sugar in a 2-quart saucepan. Cook over medium heat, stirring constantly, until butter melts and sugar dissolves. Cover and continue to cook over medium heat 2 to 3 minutes to wash down sugar crystals from sides of pan. Uncover and cook, without stirring, until mixture reaches hard ball stage (260°). If you don't have a candy thermometer, drop a small amount into a cup of cold water. If it doesn't immediately harden, continue cooking and test again.
Stir in one teaspoon of vanilla.
Remove from heat, and beat with a wooden spoon until mixture is creamy and begins to thicken. Working rapidly, spread mixture in a buttered 8- inch square pan.
Mark top of warm candy into 1-inch squares, using a sharp knife. Cool completely before cutting into squares. Wrap each piece tightly in waxed paper, twisting ends, or wrap in plastic wrap.