Place the raisins, wine and ginger in a pan, bring to the boil and simmer for 5 minutes. Transfer to a food processor and blitz to a rough purée. In the meantime, cream the butter, muscovado sugar and 20g ginger syrup together and gradually beat in the eggs. Use a little of the flour to stop the mix splitting. Add the bicarbonate of soda to the raisin mix and blend in and grate in the lemon zest.
Sift the remaining flour together with the salt and powdered ginger. Fold the flour mix into the egg mix and then fold in the raisin purée. Pour the batter into a greased 20cm loose bottomed cake tin and sprinkle the 1 tsp of muscovado over the surface. Bake at 170°c for 20 minutes and then reduce the heat to 150°c and cook for a further 15 minutes. The cake should spring back when gently pushed and be a dark brown colour.
Remove from the tin and transfer to a cooling wire. Using a pastry brush, coat the top of the warm cake with 30g of ginger syrup.
For the quince:
In a small roasting tin heat the butter, lemon juice, honey and cinnamon until melted and combined. Add the quince and toss to coat completely. Roast at 170°c for 30 minutes, basting frequently. If the pan gets too dry, add a splash of water.
To serve:
Slice the cake into wedges and place in the center of a plate or shallow bowl. Add 4 pieces of roasted quince and a quenelle of the crème fraîche. Scatter the lemon sorrel micro leaf over the quince and add viola flowers as desired.