Steak with Herb Butter, Mushrooms and Celeriac Puree

Ingredients

• 4 x 250g thick-cut sirloin steaks
• 2 tbsp olive oil
• 4 medium pine mushrooms
• 4 medium portobello mushrooms
• 12 small shiitake mushrooms
• Steamed green beans, to serve
• 100g butter, softened
• 3 anchovies, finely chopped
• 1 small garlic clove, crushed
• ½ tsp mild curry powder
• 2 tsp Dijon mustard
• 2 tbsp finely chopped chives
• 1 tbsp finely chopped parsley
• 1kg celeriac, peeled, chopped
• 2 medium potatoes, peeled, chopped
• 25g butter, chopped
• ¼ cup verjuice
• ⅓ cup pure cream, warmed
• Grated fresh nutmeg