Butter a baking pan, or line pan with baking paper, extending paper over edges of pan.

Combine sugar, salt, butter, evaporated milk and marshmallow fluff in a heavy-bottomed 3-quart sauce pan set over low heat, stirring until well blended.

Increase heat to heat to medium-high and bring mixture to a full-rolling boil being careful not to mistake escaping air bubbles for boiling.

As soon as the mixture reaches a boil, lower heat to medium and boil slowly, stirring constantly, for 5 minutes, or until mixture reaches soft ball stage (between 234 and 240 degrees F).

Remove pan from heat, add lemon essence and white chocolate pieces, stirring until chocolate is melted and well combined.

Stir in the lemon juice, which will turn this from a lemon fudge into a toffee.

Let the toffee cool down until it is still liquid enough to coat the rice bubbles without making them too soft.

Stir in the rice bubbles so they get an even coating of the toffee mixture..

Put the mixture into a large pan (I use a roasting pan lined with baking paper) and press down evenly.

Let cool on the refrigerator or freezer overnight.

Then cut into 1-inch pieces. Store in an airtight container (layers separated by wax paper) for up to a week.