Preparation: Begin by patting the top-round beef slices dry with paper towels.
Marinade Mix: In a bowl, combine vegetable oil, minced garlic, onion powder, smoked paprika, cayenne pepper, brown sugar, salt, and pepper.
Coating the Beef: Thoroughly coat each beef slice with the marinade, ensuring an even distribution of flavors. Allow it to marinate for at least 2 hours or, ideally, overnight for maximum flavor infusion.
Preheat the Grill: Fire up your grill to medium-high heat.
Cooking the Beef: Place the marinated beef slices on the grill, allowing them to cook for about 4-5 minutes per side for a perfect medium-rare doneness.
Resting Period: Once done, let the beef rest for a few minutes to allow the juices to redistribute.
Creamy Blend: In a bowl, combine mayonnaise, prepared horseradish, Dijon mustard, salt, and pepper.
Whisking Magic: Whisk the ingredients until you achieve a smooth and creamy consistency.
Slicing and Stacking: Slice the grilled beef thinly and stack it generously on freshly baked Kaiser rolls.
Horseradish Cream Magic: Spread a dollop of the horseradish cream on the beef.