Roast Beef Sandwich with Onion Confit and Havarti

Name: Roast Beef Sandwich with Onion Confit and Havarti
Cook time: 15 min
Total time: 15 min
Cuisine: American
Ingredients: 4 slices of multigrain bread or rolls split in half; 4 tsp (20 mL) soft butter; 1 tbsp (15 mL) Dijon mustard; 10 oz (300 g) roast beef thinly sliced; 1 cup (250 mL) baby spinach; 4 thin slices Canadian Havarti; 3 to 4 tbsp (45 to 60 mL) onion confit; Freshly ground pepper to taste