PREPARE: Prewarm the thermometer in hot water; use a 2-quart saucepan; butter the upper sides (inside) of the saucepan; measure all ingredients except the vanilla and optionals, and dump into the saucepan. Grease and if necessary, line a 5 X 10-inch pan. Fill glass with ice cubes and water and the sink with 1/2 inch of cold water. Dissolve the sugar, stirring constantly with a wooden spoon, over low heat until the butter melts, the gritty sounds cease, and the spoon glides smoothly over the bottom of the pan. Increase the heat to medium and bring to a boil. Boil, after washing down any crystals that may have formed, with a pastry brush dipped in hot water from the thermometer bath, using as little water as possible. Introduce the prewarmed thermometer. Reduce the heat while keeping the fudge at a boil. Stir no more than necessary. Test the fudge mixture in the ice-cold water when the mixture thickens and bubbles become noisy. Ball, formed in ice water, should hold its shape until the heat from your had begins to flatten it and should be al dente ~- slightly chewy -- between 230 and 240 (110 and 115.5 degrees C.). Because of the molasses and brown sugar, it can ball at a lower temperature than some other fudges. Shock by placing the saucepan in the cold water in the sink. Seed by adding, without stirring, the vanilla. Then allow to cool. Stir when luke warm and "skin" forms on the top (110 degrees F./43.5 degrees C.). Return the thermometer to its hot water bath to soak clean. Stir the fudge thoroughly but not vigorously by hand, with an electric mixer, or with a food processor. Pause frequently to allow the fudge to react. Watch for the fudge to thicken, lose its sheen, and become lighter in color or streaked with lighter shade, give off some heat, suddenly stiffen. If mixing by had, the fudge will "snap" with each stroke; by mixer, mixer waves will become very distinct, by food processor, fudge will flow sluggishly back to the center when the processor is stopped. Add the optionals (1/2 Cup Chopped Nuts (walnuts, pecans, or hazelnuts (filberts)) before the fudge totally candies. Pour, score, and store when cool in an airtight container in the refrigerator or at room temperature. Recipe is easily doubled and can be frozen. VARIATIONS: HONEY BROWN SUGAR FUDGE: In Step 1, eleminate the unsweetened chocolate and replace the molasses with 1/4 cup of honey. The honey causes the fudge to ball at a higher temperature. CHOCOLATE HONEY BROWN SUGAR FUDGE: In Step 1, replace the heavy cream with light cream or evaporated milk and replace the molasses with 1/4 cup of honey. ORANGE BROWN SUGAR FUDGE: In Step 1, eleminate molasses, chocolate but add 1 Tbl corn syrup. In Step 6, add 1 Tbl grated orange zest, plus if you can get it, 1 tsp of pure orange extract. PEANUT BUTTER BROWN SUGAR FUDGE: In Step 1, eliminate the molasses and chocolate, replace the heavy cream with 1/4 cup of milk and 1/4 cup of creamy peanut butter. To intensify the peanut butter flavor, add 1/3 of a cup of salted peanuts in Step 9. PRALINE BROWN SUGAR FUDGE: In Step 1, eliminating the molasses is optional -- you'ss get a more Southern praline with it, a milder one without it--or compromise and use only 1 Tbls. Eliminate the chocolate. In Step 3, when the mixture begins to thicken, add 1 1/2 cups of pecan halves slowly so as not to break the boil or cool the mixture too quickly.