Heat oven to 180C/160C fan/gas 4. Sift the flours, 1 tsp of the baking powder, a pinch of salt and cardamom in a bowl and lightly whisk together. Spoon the yogurt into another bowl with the other tsp of baking powder and stir. In the bowl of a stand mixer, whisk the eggs and sugar for about 3-4 mins, until pale and frothy.
Sift half the flour mixture into the egg and sugar mix, then use a large metal spoon or silicone spatula to gently fold it through, being careful not to knock out too much air. Once combined, scrape the yogurt into the mix and fold it in. Sift in the rest of the flour mix and fold it in again. Now pour the melted, cooled oil down the sides of the bowl and carefully but quickly fold that in. Pour in the citrus zest and juice and give it a few final folds to combine. You should have a creamy, airy batter.
Pour the mixture into silicone bundt moulds on a baking sheet. Bake for 20-25 mins, or until a skewer inserted comes out clean. Remove from the moulds and leave to cool on wire racks.
To make the glaze, heat the Campari in a pan until reduced to 1 tbsp, then pour into a bowl and allow to cool. Whisk in the orange zest and juice, a pinch of salt and the yogurt, then sieve in the icing sugar and whisk until you have a smooth glaze. Drizzle over the bundts and serve.