Preheat oven to 180°C, conventional oven mode.
Transfer butter to a small bowl and let it soften.
Take mustard out of fridge and let it come to room temperature.
Slice zucchini into rounds about 0.3 cm thick.
2. Start cooking meat
Season tenderloin with salt and pepper, then sear on all sides until browned and transfer to the oven for 5 minutes.
Do not wash the pan.
3. Cook couscous
Toss couscous with the spice blend and 1 tablespoon olive oil, pour over boiling water at a ratio of 100 ml per serving, cover.
After 5 minutes, fluff with a fork and set aside until serving. You can crumble in half of feta and fold it in.
4. Finish cooking meat
In a bowl, work the honey into the softened butter, season with salt and pepper, and add the mustard little by little. You can stop at half the amount if you want to keep it from overpowering the other flavors.
Carefully remove the medallions from the oven, coat them with the glaze, then return them to oven for another 8 minutes.
5. Cook zucchini
In the same frying pan, sear the zucchini in olive oil until nicely charred, turning it constantly.
6. Serve
Divide couscous among plates and serve with zucchini and medallions, spoon over mustard sauce still left in the baking dish. Finish with feta crumbles.