1) Knead the corn flour with the white one and with the butter into small pieces; salt, pepper and add 2/3 of the nigella seeds. If needed, add 2 tablespoons of ice water, form the dough, divide it into 2 logs, wrap them in kitchen paper and let them rest in the fridge for 2 hours.
2) Oil 16 tartlet molds, cut thick slices of dough, mash them with your palm then shape them into molds with your fingers and trim the edges with a knife. Cover the surface of each tart with parchment paper, fill with chickpeas and transfer to the oven at 180 ° for 15 minutes; remove the chickpeas and the paper and finish cooking for another 5 minutes. Remove the tartlets, let them cool and then gently unmold them.
3) Peel and coarsely chop the onion, wet it with vinegar, salt it, fry it in a pan with 1 tablespoon of oil and sugar; when it starts to caramelize, transfer it to a plate and let it cool. In a bowl, mix the goats with the milk, parmesan, half of the prepared onion and pepper. Fill the tartlets with the mixture prepared using an ice cream portioner; decorated with nigella seeds and the remaining onion and serve.