Step 1

Preheat the oven to 200°C/390F, or 180°C fan. Grease and line a 9"x9" (23cmx23cm) square tin.

Step 2

Weigh out the flour, and add in the salt and baking soda. Whisk through to remove any lumps and distribute the ingredients through the flour.

Step 3

Melt the butter, then add in the sugar and whisk through until completely dissolved. The sugar may need to be heated with the butter to completely dissolve.

Step 4

Whisk together the egg and milk. Add the milk, butter, and sweetened condensed milk to the flour. Mix with a wooden spoon until a soft dough has formed. Knead the dough a few times in the bowl, or really mix a few times after all the ingredients are combined with the wooden spoon to allow for some gluten formation.

Step 5

Press the dough into the prepared baking dish.

Step 6

Bake the rusks for 45 to 60 minutes or until a cake tester comes our clean from the centre of the rusks. The rusks will have doubled in size during the baking process.

Step 7

Allow the rusk to cool for 10-15 minutes before turning it out onto a wire cooling rack to cool completely. Once completely cooled, slice the rusks using a serrated knife. Place the rusks on a baking sheet, in a single layer, and set your oven to a maximum of 110°C/230F (cool oven), preferably with the fan on to dry the rusks out. This process can take anywhere from 3 to 6 hours, usually dependent on the thickness of your rusks.

Step 8

When the rusks are dry, store them in an airtight container, at room temperature, for up to a month. Serve with a hot cup or tea or coffee for dunking.