Thinly slice the light green and white parts of the leek and wash thoroughly. Add extra virgin olive oil to a medium skillet. Add leeks and spring peas to the hot pan and season with salt and pepper. Cook on high heat until blistered and slightly browned but still bright, about 4-6 minutes.
Wash and roughly chop mint and scallions. Add to a large bowl, along with the cooked leeks and spring peas. Give a nice glug of olive oil, squeeze of lemon, drizzle of vinegar, flaky salt and pepper. Mix and season to taste. Let it sit while you make the rest of the sandwich for the flavors to absorb.
Coat ciabatta in olive oil and cook for 2-3 min per side in same pan as the leek/pea mix until bread is browned and crispy.
Time for assembly: I like to add a layer of spinach on the bread to give a little buffer between bread and burrata (maximize crispy bread). Drizzle with more olive oil, flaky salt and pepper. Add prosciutto slices. Slice burrata balls in half and spread on top. Add spring veg mix on top. Drizzle with a little more lemon juice as you like and close sandwich.
