Directions

• Tangzhong
• Put all the ingredients in a small saucepan and mix to incorporate.
• Place the saucepan over a medium heat mixing continuously until the mixture thickens (about 30s). The texture of the mixture should be almost gelatinous.
• Take off the heat and cool it down.
• Dough
• Heat up the milk to 30C (a safe temperature for the yeast, as they would start dying at higher temperatures). Put the yeast in the milk and stir until dissolved. Let it stand for 5-8min to make sure that your yeast powder is still active.
• In a mixing bowl, combine all the dry ingredients and add the milk, followed by the tangzhong.
• Once the flour is completely hydrated, add the whisked eggs.
• When the mixture looks completely integrated, add the softened butter and knead until a smooth dough is achieved (about 10min). If it is too tough to knead, let it rest for 20min, the dough will autolyse and relax, and then you can continue. I find it more effective to transfer the dough onto a flat surface and knead in the dough spreading it with the palm of my hand.
• Fold the dough by pinching and pulling the sides of the dough up and folding in towards the centre.
• Put it on the flat surface and form into a ball by rolling it.
• Transfer the dough into a lightly oiled airtight container. Let the dough ferment in a warm place (about 24C) for 1-2h or until it has doubled in size.
• Punch the dough and move it onto a lightly floured surface.
• Divide the dough in 6 balls (95g-105g) and now we can shape the buns.
• First, fold each ball in exactly the same manner as you folded the dough before.
• Then pull the bottom of the ball towards you keeping it in constant contact with the work surface. With this motion the top of the ball should turn smooth and elastic.
• Repeat the process with all the buns. Place them on a baking tray lined up with parchment paper and cover loosely with cling film.
• Proof the buns in a warm place for 1-2h or until they double in size.
• Preheat the oven to 180C.
• Make an egg wash consisting of one egg whisked with a splash of milk.
• Lightly brush the buns with egg wash, try not to drip any on the baking tray.
• Place the buns in the oven and bake until they reach a deep golden brown colour (in our oven, about 18min).
• Once the buns are out of the oven, brush them lightly with melted butter and let them cool down.
  
• Caramelised red onions
• Heat up a medium size pan over a high heat.
• Drizzle with olive oil and drop in the sliced onions. Sprinkle with salt and mix.
• Leave the onions to cook until they start to brown from the bottom.
• Then stir them and let it brown again.
• Once the caramelised juices start collecting on the pan, pour a few tablespoons of hot water and mix to deglaze the pan (and prevent this fond from burning). Continue cooking until the water evaporates and then repeat the process again. This should take about 15-20min.
• Grilled Portobello mushrooms
• Set a medium size pan over a high heat and drizzle with olive oil. Add the mushrooms and toss in the oil. Cook them until the mushrooms are nicely browned. Take off the heat and season with salt and pepper.
• Burger patties
• Heat up a generous amount of oil on a heavy bottomed pan.
• Form the beef into two patties, but try not to break the ground beef stringy structure too much (you don’t want a meatball).
• Season generously with salt and place it on a very hot pan.
• Grill the patties until the bottom is caramelised and then flip them over.
• Take off the pan and season with black pepper.
• Cut the buns and grill them cut side down on the same pan as you used for grilling the meat. Just until they are nicely golden.
• Assembly
• To assemble the burgers, spread a very thin layer of mayonnaise on the bottom part of the bun.
• Place a few leaves of spinach (to protect the bun from getting soggy).
• Cut lengthwise 1 medium pickled cucumber, followed by the patty.
• Place the caramelised red onions and then the grilled mushrooms.
• Spread a thin layer of plum ketchup on the top layer and enjoy your burger!