Blue Steak and Potatoes - Simple Seasonal

Ingredients

• 2 lbs blue potatoes
• 2 C white onion halved and sliced (about 1 onion)
• 1 1/2 C sliced button mushrooms (about 1 8 oz package)
• 2 C baby spinach
• 2 Tbsp butter
• 1/8 tsp sea salt
• fresh cracked pepper to taste
• 1 lb sirloin steak
• 2 tsp plus 1/2 tsp olive oil
• 1/2 C sour cream
• 1/4 C blue cheese crumbles
• 2 tsp dijon mustard