Fillet of Beef, Mushroom and Stilton Rarebit Tarts with Celeriac Purée

Pastry

• 70 g salted butter, cold, diced
• 140 g plain flour, plus extra for dusting
• 40 g water, chilled

Mushroom Duxelle

• 1 shallot, halved
• 10 g unsalted butter
• 200 g chestnut mushrooms, halved
• 3 - 5 sprigs fresh flat-leaf parsley, leaves only
• 1 sprig fresh thyme, leaves only
• ¼ tsp fine sea salt
• ¼ tsp ground black pepper
• 5 g truffle oil

Stilton Rarebit

• 40 g beer
• 75 g Stilton, cut in pieces
• 100 g Cheddar cheese, extra mature, cut in pieces
• 30 g breadcrumbs
• 10 g plain flour
• 1 medium egg
• 1 egg yolk, from medium egg
• 2 tsp English mustard
• 1 dash Worcestershire sauce

Celeriac Purée

• 600 - 700 g celeriac (1 whole celeriac), peeled, cut in pieces (2-3 cm)
• 380 g whipping cream
• ½ tsp fine sea salt
• ¼ tsp ground black pepper
• 6 pieces beef fillet (175-200 g each)
• olive oil, for brushing
• fine sea salt, for seasoning steak
• ground black pepper, for seasoning steak
• 2 Tbsp fresh parsley, leaves only, chopped, for garnishing