1. If making your own bread rounds (you can also buy pre-made crostini), slice a French baguette into ⅓-inch slices. Place on a baking sheet and coat with olive oil and a pinch of salt. 

2. Toast at 400°F (205°C) for 6 mins, then flip the toasts and bake for another 6 minutes. 

3. To make the horseradish cream, finely grate a peeled horseradish root until you have about 2 tablespoons of horseradish mush.

4. Mix horseradish mush with ½ cup sour cream and a pinch of salt. Taste test, and if you prefer it less spicy, add more sour cream.

TIP: If you're pressed for time or don't want to make your own horseradish cream, you can use a premade horseradish cream or horseradish sauce.

5. Spread a thin layer of horseradish cream on the bread.

6. Add a slice of roast beef and top with a small piece of arugula.

7. Serve as-is or secure with a decorative toothpick.