1 (12 ounce) cans
- Butter an 8" x 8" pan.
- In a large, heavy saucepan, combine milk, sugar and 2 tbs margarine. Swab the top of the pan with the remaining margarine, to prevent boiling over. Cook over medium-high heat, stirring constantly, until it reaches a hard ball stage, on a candy thermometer.
- Remove from the heat and stir in the peanut butter and vanilla. Pour into prepared pan. Cool and cut into squares.