Tip the eggs, milk, yeast, flour, mixed spice, sugar and 1 tsp salt into the bowl of a stand mixer fitted with the paddle attachment. Beat until the mixture comes together into a smooth dough, then beat for 2 mins more. Gradually add the butter, 1-2 tsp at a time, while mixing on medium speed. When all the butter has been incorporated, tip in the raisins and mix for 1 min. If you don’t have a stand mixer, stir everything together in a bowl, slowly kneading in the butter using your hands, followed by the raisins. Tip the dough out onto a lightly floured surface and flatten into a square roughly 20 x 20cm. Cover and chill for 30 mins or up to 2 hrs.
Meanwhile, for the filling, beat the butter, sugar and cinnamon with a pinch of salt using an electric whisk. Set aside at room temperature. Butter a roughly 30 x 20cm baking tin and line with baking parchment. Roll the chilled dough out on a lightly floured surface to a roughly 40 x 30cm rectangle. Spread the cinnamon butter over the surface until completely covered. Roll out 400g of the marzipan on a lightly floured surface into a rectangle the same size as the dough, then lay this over the cinnamon butter layer. With a long edge facing you, roll the dough into a tight log. Cut in half to make two logs, then lift both onto a tray and freeze for 15 mins, or chill for 30 mins-1 hr mins to firm up.
Cut the chilled logs into 12 equal slices, then arrange these, spiral side-up, in the prepared tin. Leave to prove for 1 hr in a warm place, or for up to 24 hrs in the fridge until they’re about a third larger in size and are touching at the sides.
Heat the oven to 200C/180C fan/ gas 6. Bake the rolls for 20 mins. Meanwhile, roll the rest of the marzipan into 11 balls. After 20 mins, place the marzipan balls on 11 of the rolls, leaving one plain (this traditionally represents the apostles and Judas on a simnel cake). Bake for 10-15 mins more until the rolls are golden brown and the marzipan balls are toasted.
Mix the golden syrup with 2 tsp boiling water. Immediately brush the hot rolls (but not the marzipan balls) with the syrup glaze. Leave to cool slightly before eating warm or at room temperature. Will keep in an airtight container for two days.