Wash the zucchini and cut them into slices (not too thin), which you can cut into 2 or 4 pieces depending on the size of the zucchini.
Coarsely chop the onions.
Fry the onions and zucchini for about ten minutes in a frying pan with a little olive oil over medium heat.
Preheat the oven to 180°C.
Unroll the pastry and place it in a pie tin. Prick the pastry with a fork.
Brush the pastry with the mustard.
In a bowl, mix the sour cream, nutmeg, curry powder and cumin. Season with salt and pepper. Taste and adjust the seasoning to your taste.
Pour the cream and spice mixture over the zucchini and onions and mix well.
Put the mixture on the pie crust and bake the pie for about 30 minutes at 180°C.