To prepare the beef; arrange an oven rack in the center of the oven and preheat the oven to 400 °F (200 °C). Spray a heavy baking sheet with vegetable oil cooking spray. Set aside.
In a mortar and pestle or spice grinder, finely grind the cumin seeds and coriander seeds. Heat a small skillet over medium heat. Add the spices and cook for a few seconds until aromatic and toasted. Put the spices in a small bowl. Chop the garlic on a cutting board and sprinkle with 1/8 teaspoon salt. Holding a chef's knife at a 45 degrees angle, scrape the garlic and salt together to form a paste. Add the garlic paste to the bowl with the spices. Add the remaining teaspoon salt, black pepper, and oil and stir until smooth. Put the meat on the prepared baking sheet and rub with the spice mixture. Roast for 35 to 40 minutes or until an instant-read thermometer inserted into the thickest part of the meat registers 125 °F (50 °C), for medium-rare. Remove from the oven and transfer the meat to a cutting board. Cover the meat loosely with foil and let rest for 20 minutes.
To prepare the mayonnaise; in a small bowl, whisk together the mayonnaise, mascarpone cheese, basil, curry powder, horseradish and paprika until smooth. Season with salt and pepper, to taste.
To serve: Slice the meat into 1/4-inch thick slices and arrange on a platter. Spoon the mayonnaise mixture into a small serving bowl and serve alongside the sliced meat.
Note: the spices can also be crushed by placing them in a small sealable bag and crushed using a rolling pin or the bottom of a small saucepan.
There are 383 calories in 1 serving of Beef Tenderloin with Mayonnaise.