Preheat the oven to 180°C/160℃ fan/350°F/gas mark 4. Grease a 2lb loaf tin and line with greaseproof paper.
Whisk together the melted butter, oil, sugar, lemon zest and juice, milk and yogurt in a large bowl.
Add the flour, ground almonds, ground ginger and a pinch of salt and stir with a balloon whisk until fully combined, Gently stir in the chopped stem ginger.
Scrape the mixture into the prepared loaf tin and bake for about 60 minutes until a skewer inserted into the centre comes out clean.
While the cake is cooking prepare the topping. Rub the lemon zest and granulated sugar together in a small bowl and set aside. Put the lemon juice, stem ginger syrup and sugar into a small saucepan and bring up to a simmer, simmer for 30 seconds then remove from the heat.
Allow the cake to cool for 5 minutes then poke holes all over the top with a skewer. Sprinkle over the sugar and zest mixture, then drizzle over the syrup, try and make sure that the whole cake gets an even dousing. Leave the cake to cool in the tin before slicing. You can top it with extra chopped stem ginger if you like.