For the buns, line a baking sheet with a silicone mat or parchment paper.
Place yeast into the bowl of a large stand mixer: using the paddle attachment combine 100g of the flour with warm water until smooth. Allow to stand for 10-15 minutes until the mixture is foamy.
Add in the egg, melted butter, sugar and salt and thoroughly combine with the yeast mixture. Lastly add the remaining flour.
Fit a dough hook onto the stand mixer and knead the dough on low speed until soft and sticky (approximately 5-6 minutes). Transfer dough onto a floured work surface - the dough should be tacky and elastic but not wet enough to stick to your fingers. Form lightly into a smooth, round shape.
Wipe out stand mixer bowl, drizzle olive oil into the bowl and turn dough over in the bowl several times to coat the surface thinly with oil. Cover bowl with a damp clean tea towel then place in a warm place and allow to prove for a couple of hours or until doubled in size.
Once ready, transfer the dough to a floured work surface and lightly knead to burst all the bubbles. Divide the dough into eight and shape into small rolls.
Cover with a layer of greased cling film and place back into a warm space to prove again for about an hour. Brush with egg wash and sprinkle the sesame seeds on top. Place in a preheated oven (190C/170C fan/Gas Mark 5) for 15-17 minutes until lightly browned on top, then pop onto a rack and allow to cool completely.
For the prawn burgers, divide the prawns in half, then roughly chop one half and place aside. Put the rest of the prawns in a food processor and chop until a paste has been formed.
Add the parsley, coriander stalks, barbeque sauce, minced garlic, vegetable bouillon and the roughly chopped prawns together with the paste until thoroughly combined.
Divide the mixture into eight balls and form into patties about 1.5cm thick. In a lightly oiled frying pan, cook the patties over a medium heat for about 3-5 minutes on each side, making sure that the patties are cooked through before serving.
For the guacamole, place all the ingredients in a food processor and blend until smooth. Taste and season accordingly.
To serve, slice the buns in half and place a burger and a generous dollop of guacamole in the centre of each one. Garnish with the leaves of a gem lettuce. A red onion and cherry tomato salsa compliments these sliders perfectly.