Preheat oven to 400 degrees. Peel the carrot and parsnip, then slice into 1/2-inch thick spears (like steak fries). Cut the garlic cloves in half. Set two small rosemary sprigs aside for garnish, then pick the remaining rosemary leaves off the stems and roughly chop. Discard the stems.

Toss the carrots, parsnips, and chopped rosemary on a baking sheet with 1 tablespoon oil and a pinch of salt and pepper. Place in the oven for about 25 minutes, tossing halfway through cooking, until tender and slightly caramelized.

Rub the steak thoroughly with the halved garlic cloves, then season with salt and pepper. Heat 1 teaspoon oil in a large pan over medium heat. Add the garlic to the pan and cook for about 1 minute, until slightly golden brown. Remove from pan and discard.

Increase heat to medium-high and add the steak to the pan. Cook 4-7 minutes per side, until cooked to desired doneness. Set aside to rest for 5 minutes.

Make the horseradish sauce: in a small bowl, combine the sour cream, vinegar, and horseradish, to taste (start with 1 teaspoon and go up from there). Season with salt and pepper.

Thinly slice the steak against the grain and serve alongside the roasted vegetables. Drizzle the steak with the horseradish sauce and garnish with a sprig of rosemary. Enjoy!