Method

• 1.
  Place flour, fennel, yeast and sugar in a large bowl. Gradually add buttermilk and 200ml lukewarm water, mixing well to form a very soft dough. Add 2 tsp salt flakes and mix thoroughly. Use your hands to knead the dough, stretching it from underneath to over the top. Repeat for 5 minutes or until dough feels smooth and stretchy. Transfer to a clean, lightly reased bowl, cover with plastic wrap or a tea towel, and set aside at room temperature for 1 hour or until doubled in size.
• 2.
  Knock back the dough, cover again with plastic wrap or a tea towel and place in the fridge to rise overnight. The next day, remove dough from the fridge and set aside in a warm place for 3 hours or until at room temperature.
• 3.
  Preheat oven to 220°C. Grease a 25cm x 36cm baking pan with 1 tbs olive oil. Transfer risen dough to prepared pan, gently pushing it into the corners, and drizzle with remaining 2 tbs olive oil. Set aside for 30 minutes or until dough has risen by about one-third.
• 4.
  Once risen, use your fingers to create dimples all over the focaccia. Bake for 25 minutes or until golden on top.
• 5.
  Meanwhile, melt 50g butter in a frypan over medium heat. Add garlic and eschalot and cook for 2-3 minutes until softened. Add mushrooms and cook for 4-5 minutes. Add 1/2 tsp freshly ground black pepper, a pinch of salt flakes, remaining 40g butter and thyme. Toss until butter has melted.
• 6.
  Remove focaccia from oven and spoon over mushroom mixture. Tear over burrata, drizzle with extra olive oil and season with freshly ground black pepper to serve.