1. Preheat the oven to 200°C (392°F) (thermostat 6/7).
2. Separate the egg whites from the yolks.
3. In a bowl, beat the egg whites until stiff with a pinch of salt.
4. Beat the yolks, add the flour, cornstarch, baking powder, butter, paprika, tomato paste, and gruyère cheese. Mix well and gently fold in the beaten egg whites.
5. Spread the mixture onto a baking sheet lined with parchment paper and bake for 10 minutes.
6. Mix the goat cheese with the cream cheese. Add the chopped chives and season with pepper.
7. Once cooked, roll the cake tightly and cover with a kitchen towel. Set aside and let it cool.
8. Once cooled, unroll the cake and spread the cheese/cream cheese mixture on top.
9. Roll the cake tightly again, wrap it in plastic wrap, and refrigerate for at least 2 hours.
10. Remove the plastic wrap and slice before serving.