To help the dough rise, you need a warm place. You can preheat your oven at a little over 50°C for 10 minutes. Turn off the oven and keep it closed while you make the dough.
Attach the kneading hook to your stand mixer (the whisk attachement works as well) Add the flour to the mixing bowl of your stand mixer (or a large mixing bowl if you're using a hand mixer).
Crumble the yeast over the flour. Heat the plant-based milk until lukewarm (30 seconds in the microwave or several minutes over the stove) and pour it over the yeast. Start kneading on low.
Add the sugar and vanilla sugar while it's kneading. In the meantime, heat the margarine (30 seconds in the microwave or 1-2 minutes over the stove) until it's half melted. Add it to the mixing bowl as it continues kneading.
Finally, add the egg and a pinch of salt. Let it knead for 15 minutes (I recommend setting a timer). If you're using a hand mixer, beat it for at least 10 minutes on low.
Form a ball with the dough. It is slightly sticky but you should be able to easily form a ball (see step-by-step pictures in the post above). If not, try humidifying your hands or adding 1 tablespoon of flour.
Sprinkle a little flour into a bowl and place the dough in it. Cover with a humid towel and let it rise in the preheated oven or in a warm place for 1 hour.