Cook the potatoes
Cut the new potatoes in quarters and put them into a pot filled with salted water. Place over high heat and cook until the water starts to boil, lower the heat and cook for another 5 minutes. Drain the potatoes in a colander and leave them for about 10 - 15 minutes. Preheat the oven to 240 °C / 465 °F.
Line your roasting tray with baking paper. Toss in the potatoes, drizzle with olive oil and season to taste with black pepper and cayenne pepper. Add a sprig of thyme and a spring of oregano. Toss together with your hands until coated. Place in the oven and bake for 20 minutes at 220 °C / 430 °F.
Herb dipping sauce
Prepare the Herb dipping sauce: In a small bowl combine together sour cream, tabasco sauce, olive oil, chopped herbs and chopped scallions. Season to taste with salt and pepper.
Wash fresh asparagus under cool running water and remove the woody ends. Blanch them in boiling water for about 30 second, then transfer them to a bowl of ice water to cool it down.
Remove the tray from the oven, push potatoes on one side and place the trout fillet on the other side of the baking tray. Place back into the oven (middle rack) and bake for another 5 - 8 minutes at 240 °C / 465 °F. Remove from the oven and serve with asparagus and herb dipping sauce served on the side.TipIf you have a really thick trout fillet, bake it for 2 - 4 minutes further.