Start by making the peach ketchup. Put the shallot and oil into a small saucepan over a medium-high heat for 4-5 mins or until sizzling and starting to soften. Add all the other ketchup ingredients bring to a simmer then take off the heat. Allow to cool briefly, then place into the bowl of a food processor. Blitz until smooth then pour everything back into the saucepan. Bring to the boil and reduce for 3-4 mins or until thick. Remove from the heat and set aside until needed.
To make the burgers put the porcini mushrooms into a small bowl and pour over 1 tbsp boiling water and allow to steep until soft. Meanwhile, put 1 tsp of oil into another saucepan and cook the chopped button mushrooms until soft and all the liquid has evaporated. Chop the porcini mushrooms and add to the pan along with the butter beans. Remove from the heat and using a potato masher squish everything together until the butter beans are completely mashed and are thoroughly mixed with the mushrooms. Tip the mixture into a bowl and stir in a crushed garlic clove and season well with salt and pepper.
When cool enough to handle, shape the bean and mushroom mix into 2 large burger patties and place on a plate ready for cooking.
Heat oven to 180C/160C fan/gas 4. Cut each of the ciabatta rolls in half through the middle. Carefully pull out a little of the bread from the middle of the bottom half of each roll, leaving the crust in tact. You just want to make a little extra space here for the salad. Tear the bread you have pulled out into small chunks and place onto a baking tray along with the cut halves of the rolls. Place in the oven for 5-6 mins or until warmed through and the bread pieces are a little drier.
To make the panzanella-style salad put the toasted pieces of bread into a bowl along with the cherry tomatoes, capers, sundried tomatoes and the oil. Season with salt and pepper.
Lay the avocado halves on a plate, pour over the lemon juice and sprinkle with the chives.
Heat the remaining oil in a large non-stick frying pan and cook the bean and mushroom burgers for 3-4 mins on each side, try not to turn them too much as they can break up a little, if they do just push them back together with a spatula.
To build the burger, fill the cavity in each of the bottom halves of the burger buns with the panzanella salad. Balance the burger on top of the salad, then top with the cheese, followed by the peashoots, and avocado. Spread the peach ketchup on the top pieces of the roll to finish Serve immediately with any remaining ketchup on the side to dip.