Prepare the passion fruit curd by adding all the ingredients to a heavy bottom pan and simmer, letting the mixture come to a boil. Once it begins to thicken, take it off the heat and let it cool. The curd will be of a thick, pourable consistency when it is at room temperature.
To prepare the cake, centre a rack in the oven and preheat the oven to 350 F (180 C). Prepare a 8 1/2-x-4 1/2-inch loaf pan, by buttering it, dusting it with flour and dusting off the excess.
Whisk together the flour, ground almonds, baking powder and salt and keep aside.
In a medium bowl, add the yoghurt, eggs, passion fruit curd and vanilla to the bowl and whisk vigorously until the mixture is very well blended. Still whisking, stir in the dry ingredients, then fold in the oil. Scrape the batter into the pan and smooth the top.
Slide the cake pan into the oven and bake for 35 to 40 minutes at 180C. It should be golden brown and a knife inserted into the centre of the cake should come out clean. Transfer the pan to a rack, cool for 5 minutes, then run a blunt knife between the cake and the sides of the pan. Unmold and cool to room temperature right-side up.
Serve with a drizzle of passion fruit curd.