This recipe has enough white chocolate to capture attention, but not enough to overwhelm. For deeper flavour, use up to 340 g (12 oz) white chocolate.
500 ml (2 cups ) granulated sugar
175 ml (3/4 cup) sour cream
125 ml (1/2 cup) butter or margarine
Pinch salt
Freshly grated zest of 2 lemons
250 g (8 oz) white chocolate, coarsely chopped
1 jar (198 g/7 oz) marshmallow creme
5 to 7 ml (1 to 1 1/2 tsp) pure lemon extract
1 to 2 drops yellow food colouring (optional)
Butter a 20-cm (8-inch) square pan or line with buttered parchment paper, leaving a generous overhang.
In a heavy saucepan over medium heat, bring sugar, sour cream, butter, salt and lemon zest to a boil, stirring until sugar dissolves and mixture begins to boil. Cook, stirring occasionally to prevent scorching, to soft ball stage (112 to 116 C/234 to 240 F, with 114 C/238 F recommended).
Remove from heat. Stir in chocolate until melted. Add marshmallow creme and lemon extract. Stir until candy is smooth and well blended. Stir in food colouring, if using. Pour into prepared pan.
Let cool to room temperature, chill and cut into squares. Store in an airtight container.
Makes about 1 kg (2 lb).