Begin by preheating your oven to 180°C (350°F).
In a mixing bowl, combine the cake flour, butter or margarine, and chopped fresh herbs or dried herbs. Mix until the mixture resembles coarse crumbs.
Add the ice-cold water and the egg yolk into the mixture, and stir until it forms a dough. Wrap it in plastic wrap and refrigerate for 30 minutes.
While the dough is chilling, heat a skillet over medium heat. Add the chopped chicken breast fillets, onion, and minced garlic, cooking until the chicken is no longer pink and the onions are translucent.
Stir in the sundried tomatoes and cook for an additional 2-3 minutes. Remove from heat and let it cool slightly.
In a bowl, whisk together the extra-large eggs, sour cream, and chopped fresh herbs until well combined.
Roll out the chilled dough on a floured surface and cut it into circles to fit your mini quiche pans. Press the dough into the pans.
Evenly distribute the chicken mixture into the pastry shells, then pour the egg and sour cream mixture over the top.
Bake in the preheated oven for 20-25 minutes or until the quiches are set and lightly golden.
Allow to cool for a few minutes before serving warm. Enjoy your delicious mini chicken quiches!