Oil a 23cm cake tin with a depth of at least 7cm, then line the base and sides with baking parchment. Heat the oven to 180C/160C fan/gas 4. Combine the flour, bicarb, spices and sugar in a large bowl with 1/4 tsp salt. Using your fingertips, rub the floury mixture for a few minutes to squash out any lumps of sugar into the flour.

Whisk the oil, eggs, milk and vanilla extract in a jug and pour into the dry ingredients. Add the grated carrot, chopped pineapple and walnuts (if using), then fold everything together with a spatula.

Scrape the mixture into the tin and level the top with the spatula. Bake for 1 hr until risen and a skewer inserted into the centre comes out clean. If there is any raw cake mixture sticking to it, return to the oven for 5 mins, then check again. Leave to cool in the tin for 15 mins, then transfer to a wire rack and spoon 1 tbsp pineapple juice (if using canned pineapple) over the sponge. Leave to cool completely.

To make the icing, beat the butter and half of the icing sugar together, by hand or using an electric whisk, until smooth. Add the rest of the icing sugar and the vanilla and beat for a few more minutes until smooth, then mix in the soft cheese. Put the cake on a plate or cake stand and pile the icing on top. Arrange the pineapple flowers on top, if using (see below for the recipe). Will keep in an airtight container in a cool place for two days.