Grease a microwave-safe pudding bowl with butter and sprinkle with flour.
Blend the flour, sugar, ginger, baking powder, and butter in a food processor.
Mix in the eggs until a sticky dough forms.
Transfer dough to the bowl, cover with film, and microwave on full power for five minutes.
Simmer vanilla seeds, pod, milk, and cream in a small saucepan.
Remove from heat and let the mixture infuse.
Beat egg yolks and sugar together in a large bowl.
Remove the vanilla pod and whisk the warm cream into the egg mixture.
Heat the custard gently until it thickens enough to coat a spoon.
Heat sugar and Brazil nuts in a pan until the sugar caramelizes into a deep amber.
Pour onto a cold non-stick surface and allow to set.
Shatter the set brittle using a rolling pin.
Drizzle custard over the sponge and garnish with brittle pieces.