Warm up beetroot juice lukewarm. Prepare the dough with 2 tbsp. olive oil and juice instead of water and let it rise.
Clean and wash the zucchini and slice lengthwise into strips with a peeler. For the pesto, wash parsley and shake dry. Pluck off the leaves and chop them coarsely. Coarsely chop the walnut kernels. Coarsely grate half of the Parmesan cheese. Finely puree parsley, walnuts, grated Parmesan and 100 ml oil with a hand blender. Stir in lemon zest. Season to taste with salt and pepper. Stir half of the pesto with cream cheese until smooth. Sort the rocket, wash and drain well.
Preheat oven (electric cooker: 220 °C/circulating air: 200 °C/gas: see manufacturer). Line baking tray with baking paper. Halve the dough, roll out and place on the baking tray. Spread half the cream cheese on top, leaving a small rim. Cover with half of the zucchini. Bake in a hot oven for 12-15 minutes.
Pat the steak dry. Cut the edge of fat with a sharp knife so that the steak does not bend during roasting. Heat 1 tablespoon of oil in a frying pan. Fry the steak for 1 minute over a high heat, then fry on each side for approx. 3 minutes. Season with salt and pepper.
Slice the rest of the parmesan. Cut the steak into slices. Take the tarte flambée out of the oven, cover with half of the steak strips, rocket salad and parmesan. Prepare and bake the 2nd tarte flambée in the same way. Add the rest of the pesto.