60mlmilk(I used whole and recommend that but part/semi-skimmed also ok)
1egg yolk
½teaspoonvanilla extract
For plum layer
400gplumssmall and pos more tart eg damsons/Italian prune plums
½tablespoonsugar(optional, or increase if tart plums)
For streusel
48gall purpose flourplain flour
¼teaspooncinnamon
22gunsalted butter
33gsugarI suggest ½ of this raw or demerara, rest regular
Instructions
For base and plums (1hr ahead)
Lightly butter an 8x8 inch (20x20cm) baking dish or tin. Mix together the dry ingredients for the base - flour, sugar, yeast and salt - in a medium bowl.
Put the butter and milk into a small microwavable dish and warm in 15 second intervals to gently warm the milk and melt the butter. The butter should be just melting and the milk lukewarm. Add this mixture (left to cool first, if too warm), the egg yolk and the vanilla to the dry ingredients and mix all together.
Knead the dough gently for a minute or two - it should be soft but not wet so add a little more flour if too wet, or milk if it seems to crumble from being dry. Then, press the dough into the buttered baking dish. Press it right to the corners, flat across the bottom then slightly up at the edges.
Cut the plums in half, along the bit that looks like a seam, then remove the stone. Cut each plum half in half. Arrange the plum quarters over the base as tightly as you can, ideally in rows, cut side up. Leave the dish at warm room temperature to let the dough rise slightly for approximately 1 hour (don't worry if it doesn't obviously change much).
Adding streusel and baking
As the rest time is about done, preheat the oven to 350F/180C. Sprinkle the ½tbsp of sugar over the plums, if using.
Rub together the flour, cinnamon, butter and sugar for the streusel then sprinkle it evenly over the plums.
Bake the cake for approximately 30 -35 minutes, until the top is gently starting to brown and you can see the plums have softened underneath. Let the cake rest for around 10 minutes before cutting into slices. Works well as it is, both warm or at room temperature, as well as with cream.