• In a small bowl dissolve the yeast in 25ml of the warmed milk. Stir in 1 teaspoon of the sugar and 1 teaspoon of flour, then set aside for 10 minutes. Meanwhile, using the dough hook attachment of a stand mixer, knead the remaining dough ingredients together until smooth - 5-7 minutes. (note: for kneading by hand, see tips and tricks below)
• Add the yeast mixture to the dough and continue to knead until all the liquid has been absorbed by the dough - it will initially look very wet, but have patience and keep kneading. When the liquid has been absorbed and the dough moves freely in the bowl, which will take around 5 minutes, remove the dough from the bowl, shape into a ball, cover with cling film, return to the bowl and set aside in a warm place for 1 hour to rise.
• While the dough is rising, make the crumble topping by whisking together the flour salt and sugar. Cut small pieces of the softened butter into the mixture, then gently rub in using your fingers until you have a loose pebbly mixture. Pour over the melted butter and use a fork to roughly stir it through - this is the trick to creating those deliciously buttery pieces of streusel. Break up any that are overly large with your fingers. Put the crumble topping in the fridge until the dough has risen.
• When the dough has risen, heat the oven to 180°C / 350°F / Gas 4. At this point, you need to decide whether you want to make individual or one large cake. For the individual cakes line two trays with baking paper, for the larger cake, line one.

For the individual cakes:

• Knock the air out of the dough (it should no longer be at all sticky) and divide into 10 equal-sized pieces - I find it is easiest to weigh the pieces so the are the same - about 70g each. Form each piece of dough into a ball, then stretch out into a circle 10cm in diameter, pressing down the middle so the edges are slightly raised, placing each on one of the two trays. Divide the red currants between the dough pieces and squeeze with a little lemon juice and sprinkle over a little sugar. Top generously with the crumble mixture, and here I have to stress, just scatter it over, do not press it down, then bake in the oven (I do this in two lots rather than all the same time) for 20 minutes each tray.

For the large tray cake:

• Knock the air out of the dough (it should no longer be at all sticky) and on a lightly floured surface roll the dough out to a large rectangle nearly the size of your tray. Transfer to the lined tray and use your fingers to stretch the dough into the corners, pressing down to leave a slightly raised edge all the way around. Top with all of the red currants, scatter over the crumble topping and bake in the preheated oven for 30-35 minutes.
• Allow to cool on the tray. When cool, whisk together the icing sugar and lemon juice and drizzle a little over each cake, or alternatively dust with plenty of icing sugar just before serving.