Grandma finds fudge too sweet, but Lucy and the other grandchildren love every sticky bite. Just making this recipe is as much fun as eating it, with a sugar thermometer involved and Grandma on watch to supervise the proceedings.

Makes 2 lb/1 kg fudge
3 cups/600 g sugar
1 cup/250 ml milk
2 tablespoons light corn syrup
200 g/7 oz dark chocolate, chopped
3 tablespoons/90 g butter, more for the pan
1 teaspoon vanilla extract
1 cup/150 g chopped walnuts or pecans
8-inch/20-cm square loaf pan; sugar thermometer

1. In a saucepan over a medium heat, heat the sugar, milk, corn syrup and chocolate to boiling, stirring constantly and washing any crystals from the side of the pan with a wet pastry brush. Continue to simmer the mixture, stirring often, until the temperature reaches 238˚F/114˚C on a sugar thermometer (soft-ball stage), 12-15 minutes.

2. Take the pan from the heat, stir in the butter and vanilla and let the mixture cool without stirring to 110˚F/43˚C or until the outside of the saucepan feels only lukewarm. Meanwhile butter the loaf pan and line it with wax paper, leaving an overlap at each side.

3. When the fudge mixture has cooled and begins to lose its gloss, quickly stir in the chopped walnuts or pecans and spread the fudge in the prepared pan, pushing it into the corners. Leave the fudge to cool completely and set firm, at least 2 hours.

4. Using the paper overlaps, lift the fudge onto a wooden board. With a sharp kitchen knife, cut the fudge into 1½-inch/4-cm squares and separate them. Pack the fudge with wax paper between the squares and store in an airtight container. It keeps well for a week or more.