Montreal Grilled Beef Sirloin

Name: Montreal Grilled Beef Sirloin
Prep time: 30 min
Cook time: 30 min
Yield: 4 to 6
Cuisine: Canadian,
Ingredients: 2 green onions, chopped; 3 sprigs Italian parsley, leaves only, chopped; 125 g (1 stick) salted butter, softened; 25 ml (2 tbsps) montreal steak spice seasoning; 10 ml (3 tsps) capers, chopped; 50 ml (1/4 cup) olive oil, divided; 1 package (680 g) multi-colored miniature potatoes; 4 beef sirloin steaks (about 250 to 300g); 60 ml (1/4 cup) mayonnaise; 10 ml (2 tsps) honey; 10 ml (2 tsps) lemon juice; 25 ml (2 tbsps) Dijon mustard