In a large bowl, sieve together the plain white flour, strong white bread flour, cornstarch, baking powder, fine sea salt and sugar. Mix well to combine. Set aside.
125 g plain white flour, 35 g strong white bread flour, 2 tablespoon cornstarch, 4.5 teaspoon baking powder, 1 teaspoon fine sea salt, 1.5 teaspoon sugar
In a measuring jug, whisk together the soy milk, aquafaba, water and vinegar (in this order). Add to the dry ingredients and whisk until just combined and you have a smooth batter.
185 g soy milk, 70 g water, 1.5 teaspoon white wine vinegar, 195 g aquafaba
Cover the batter and allow to rest at room temperature for at least one hour.
Once rested, preheat the oven to 220 °C.
When the oven is hot, use the vegetable shortening to grease the insides of the holes in a deep 6 hole muffin tin. Add an extra 1 teaspoon of shortening to each hole and place it in the pre-heated oven for 5-7 minutes or until the shortening is completely melted and very hot.
6 teaspoon vegetable shortening
Working quickly, evenly divide the batter between the 6 holes (pour the batter in a circular motion onto the sides of the holes – this traps a little well of oil in the centre which helps to form the hole in the middle). Quickly return the tin to the oven and bake for 10 minutes.
Remove the tray from the oven - the puddings should be pale and puffed up like muffins. Use a lightly greased tablespoon measure or a teaspoon to push down a hole in the centre of each pudding. Return the puddings to the oven and bake for a further 15 minutes.
Remove the tray from the oven and carefully remove the puddings from the muffin tin and place them on a baking sheet - they should be lightly golden by this point. Return the puddings to the oven for a further 10 - 15 minutes or until golden and crispy all over.
Remove from the oven and either serve immediately or allow to cool to room temperature. Transfer to an airtight container and freeze for up to 3 months. When ready to serve, reheat in the oven at 160 °C for 10 minutes.
Notes
Note: I strongly recommend using an electronic scale for this recipe. The measurements need to be relatively exact and I advise against using cups for this recipe. And yes, the liquid measurements are in grams, not ml (even though 1g is equal to 1ml of water). I weigh all of my liquid ingredients because this makes it easier to be exact.