Savory and Rich Grilled Chicken Avocado Sandwich – Wives With Knives

Ingredients

• 2 boneless skinless chicken breasts
• 1 ripe avocado
• 4 slices whole-grain bread
• 1 medium tomato
• 1/2 small red onion
• 2 cup baby spinach
• 2 tbsp olive oil
• 1 tbsp balsamic vinegar
• 1 tsp dijon mustard
• salt and pepper to taste