This open-face roast beef sandwich requires minimal ingredients and makes for a delicious snack. If you like a little more spice, feel free to use spicy horseradish sauce. Easily customizable, these are great for a picnic or brunch appetizer.
In a small bowl, combine sauce ingredients (horseradisch sauce, milk, and chutney)
Spread one side of each bread slice with 2 teaspoons sauce. Top with equal amounts of cucumber, onion and deli roast beef. Spoon remaining sauce evenly over beef; sprinkle with chives.