The idea of adding fennel to the sugar coating for the pineapple comes from Phillip Searle's famous chequerboard ice-cream of the late '80s. He used star anise and licorice, but I've tried to simplify with ground fennel seeds. Orange zest in the batter adds complexity to the pineapple – a partnership which cook and flavour expert Niki Segnit describes as having "all the joie de vivre of a Hawaiian shirt without the stigma of wearing one". That's got to be a good thing!
For the pineapple topping
20g unsalted butter, softened
80g light brown sugar
½ tsp fennel seeds, finely crushed using a mortar and pestle
¼ tsp salt
1 medium pineapple (about 1kg)
For the batter
180g plain flour
3⁄4 tsp baking powder
½ tsp baking soda
¼ tsp salt
100g unsalted butter, at room temperature
80g caster sugar
40g light brown sugar
zest of 1 large orange
2 eggs at room temperature
150g sour cream, plus extra to serve
1 tsp vanilla extract
1. Prepare a loaf tin (about 23cm x 13cm) by lining with parchment paper, then smear the bottom of the tin all over with the softened butter. Preheat the oven to 175C fan-forced (195C conventional).
2. Mix the brown sugar, fennel and salt together on a plate (it needs to be large enough to fit long pineapple spears), then set aside.
3. Slice the top and bottom off the pineapple, then stand it on one of the ends. Using a sharp knife, remove the peel by slicing downward, then remove the "eyes" with a small knife. Now slice the pineapple in half vertically, and place on a chopping board with the flat surface on the board. Slice lengthwise into 2cm-thick pieces (slice straight down so that you get rectangles rather than wedges), then trim away the core from each piece. You will need 6-8 pieces (depending on the size of your tin). Save the rest of the pineapple for eating.
4. Trim the pineapple pieces so that they are the same length as the width of the loaf tin. Then, one at a time, roll each piece in the brown sugar mixture so that they are coated all over. Place the pieces across the bottom of the tin so that they fit snugly, then sprinkle any leftover sugar mix over the fruit. Set aside.
5. Sift the flour, baking powder, baking soda and salt together in a small bowl, then set aside.
6. Place the butter, sugars and orange zest in the bowl of a cake mixer fitted with the paddle attachment and beat on medium-high speed until light and fluffy – about 2 minutes. Add the eggs, one at a time, and beat well to incorporate after each addition. The mixture will look curdled at this point, but don't worry, it will smooth out with the addition of the flour. Scrape the bowl from time to time to make sure there are no lumps, then on low speed, add the sifted dry ingredients, alternating with the sour cream. When almost combined, remove the bowl from the mixer, add the vanilla extract and finish folding the batter with a spatula – this ensures the batter is not over-mixed, which can result in a tough, chewy cake.
7. Scrape the batter into the loaf pan, directly on top of the pineapple. Smooth over the top and place in the oven for 45-50 minutes. The cake will be done when a skewer inserted into the centre comes out clean. Remove from oven and cool for 10 minutes before inverting the cake onto a wire rack to cool further. Serve with sour cream on the side.