Heat the oven to 180C/160C fan/ gas 4 and line a 12-hole muffin tin with paper cases. Combine the flour, baking powder, mixed spice and sugar in a large bowl. Combine the eggs, clementine zest and juice and the oil in a small bowl or jug.

Stir the grated celeriac and chopped hazelnuts into the flour mixture, then stir in the egg mixture. Continue to stir until everything is almost combined, but a few specks of flour remain. Divide the batter between the muffin cases so they’re two-thirds full. Bake for 20-25 mins until lightly golden and a skewer inserted into the middles comes out clean. Leave to cool in the tin for a few minutes, then transfer to a wire rack to cool completely.

To make the frosting, sift the icing sugar into a bowl, beat in the soft cheese, a pinch of the clementine zest and a little of the juice until thick. If it’s too loose, chill for up to 30 mins. You can also sift in extra icing sugar if needed. Once the muffins are completely cool, pipe or spoon over the frosting, and top with bashed hazelnuts, if you like. Will keep chilled in an airtight tin for three days. Bring back to room temperature before eating.