1. Preheat your oven to 200°C (thermostat 7).
2. Peel and thinly slice the turnips and sweet potatoes.
3. Finely chop the onion.
4. Cook the sweet potatoes in a pot of boiling water.
5. Meanwhile, heat olive oil in a pan and sauté the chopped onion until translucent, then set aside.
6. In the same pan where the onion was cooked, add honey and 2 tablespoons of water.
7. Add the turnips and cook over low heat until they are slightly golden.
8. In a bowl, mix together the cream, eggs, onions, and feta cheese.
9. Roll out the pie crust in a non-stick tart pan, spread the vegetables evenly, and cover with the cream mixture.
10. Sprinkle some sesame seeds on top of the tart.
11. Bake for 30 minutes at 200°C.