In a large bowl combine the butter and 100 g sugar and beat until fluffy. Add the flour, baking cocoa, baking powder and salt and mix well. Stir in the plant-based milk and apple sauce. Finely chop the dark chocolate and fold into the batter. To make the filling, first drain the Silken Tofu in a sieve, then place it in a small pot.
Scrape the pulp from the vanilla pod and combine with the Silken Tofu along with the turmeric and sugar. In a separate small bowl, whisk the starch into a small quantity of liquid from the pot until smooth. Continue stirring the Silken Tofu mixture and bring to a simmer. Whisk in the starch slurry and gently simmer for another minute until the mixture begins to thicken, stirring constantly. Remove from heat. Let cool for 15 minutes.
In the meantime, preheat the oven to 180° C using the convection bake setting, and line a muffin tin with paper muffin cups. Fill the muffin cups 2/3 up with chocolate batter. Top each with 1-2 teaspoons of the Silken Tofu mixture, and gently swirl this into the batter with a fork. Bake the muffins on the middle oven rack for 25 minutes.