The night before (or at least 2 hours ahead), place the prunes in a small bowl and pour over the brandy.
Cover and leave them to soak and plump up.
When you're ready to bake, preheat your oven to 155°C (310°F) / 135°C Fan / Gas Mark 3.
Grease a 26 x 12cm / 10 x 5 inch loaf tin with butter and line it completely with baking parchment.
Spread the walnuts on a small baking tray and toast in the preheated oven for 20-25 minutes until fragrant and golden.
Set aside to cool, then roughly chop.
In a large mixing bowl, whisk together the eggs, sunflower oil, muscovado sugar, and 4 tbsp (60 ml) of honey until well combined. A stand mixer with a beater attachment works well here.
Sift in the self-raising flour, baking powder, and salt.
Drain the soaked prunes but be sure to reserve the leftover brandy for the glaze.
Fold the drained prunes, toasted walnuts, and orange zest into the batter until just combined.
Pour the batter into your prepared loaf tin and smooth the top.
Bake for 50-55 minutes. The cake is ready when it's firm to the touch and a skewer inserted into the centre comes out clean.
Let the cake cool in the tin for 10 minutes before carefully turning it out onto a wire rack to cool further.
To make the glaze, gently heat the remaining 2 tbsp (30 ml) of honey with 1 tbsp (15 ml) of water in a small saucepan.
Remove from the heat and stir in the reserved brandy from the prunes.
While the cake is still warm, use a skewer to poke holes all over the top, then brush the glorious brandy glaze all over, letting it soak in.