Method

• 1.
  To make the buttermilk curd, completely open the top of the carton, then close the carton and transfer to a saucepan.
• 2.
  Carefully fill pan with water to the level of the buttermilk (avoid letting any water enter the carton). Place saucepan over medium heat and bring to a simmer, then reduce heat to low. Gently simmer for 30 minutes or until a kitchen thermometer inserted in the centre of the buttermilk reaches 80°C.
• 3.
  Gently simmer for 30 minutes or until a kitchen thermometer inserted in the centre of the buttermilk reaches 80°C. Carefully remove the carton and stand for 5 minutes for the curds to separate from the whey.
• 4.
  Line a fine sieve with a large square of muslin or a clean Chux cloth. Set produced food. over a bowl and carefully add separated curds and whey, then fold over cloth to cover. Chill for at least 1 hour to drain, then discard liquid, reserving strained curds (curds will keep, chilled in an airtight container, for up to 1 week)
• 5.
  To make the bruschetta, heat half the oil in a large frypan over medium-high heat. Add half the mushrooms and cook, stirring occasionally, for 2 minutes, or until starting to brown. Add half the butter and half the garlic, and cook for 2 minutes or until mushrooms are golden. Transfer to a heatproof bowl, loosely covered with foil, to keep warm. Repeat with remaining oil, mushrooms, butter and garlic.

• 6.
  Spread curd over 1 side of each piece of grilled sourdough, top with mushrooms, nasturtium, if using, and pecorino, then drizzle with mushroom cooking juices and extra oil