Fill a big pasta pot with well salted water. Bring to a boil. Meanwhile, fill a large bowl with ice and water to make an ice bath. Put a colander in the sink.
Once the water has reached a rolling bowl, add the green beans to the water. Cook for 2 minutes until they have reached a nice green colour. Use a slotted spoon or tongs to remove them from the water, and place directly in the ice bath. Once cooled, remove from ice bath and dry. Replenish ice bath with more ice and water.
Cook the eggs: Using a slotted spoon, lower the eggs one at a time into the boiling water. Turn the heat down slightly so the boil is not too aggressive and boil for 7 minutes. As soon as timer goes off, use slotted spoon to place eggs directly into the ice bath. Once cooled, remove from ice bath, peel and halve. The yolks should be perfectly jammy!
Cook the potatoes: Add them to the same pot of still boiling water, cook for approximately 15 minutes or until a knife slides through nicely. Strain in a colander and run under cold water so they're room temperature.
Make the dressing by whisking all the ingredients together, or shake in a glass mason jar.
Assemble the salad on a platter, grouping ingredients together. Season everything with salt and pepper. Either drizzle with dressing or let everyone help themselves.