In a saucepan, heat oil, black peppercorns, star anise, coriander seeds, and Szechuan peppercorns for 1 minute until aromatic. Stir in red curry paste, tamarind paste, and honey. Deglaze with Madeira and reduce until syrupy. Add the veal stock and continue to reduce in half. Transfer to a blender and process to a puree. Strain and set aside.
Over hot grill, cook the tenderloin until grill marks appear on all sides. Transfer to a saute pan and pour in half of the strained sauce. Roast in the oven for 4 to 5 minutes or until desired doneness.
Transfer the remaining sauce to a saucepan and cook over medium heat. Reduce until thickened. In a cup, dissolve the powdered mustard in rice wine vinegar. Whisk in mustard and finish sauce with the butter.
To serve, cut the steak into thin slices. Nap with Madeira Mustard Sauce and serve with Wasabi Mashed Potatoes garnished with a whole star anise.
Wasabi Mashed Potatoes:
Cut the potatoes into large pieces of equal size. Cover with salted water. Bring to a boil and cook until tender. Drain thoroughly. Pass through a food mill and whip in the butter, hot cream and roasted garlic puree.
Blanch the spinach in boiling salted water for 10 seconds. Refresh in ice water. Drain thoroughly. Transfer to a blender and add wasabi powder. Process to a puree. Stir into warm mashed potatoes. Season with salt and pepper, to taste.