Rinse the potatoes: Rinse the potatoes rubbing any dirt off and leave the skins on.
Cook the potatoes: Add the potatoes to a large pot, top them up with regular cold tap water, add a tablespoon of salt, lid on and bring to the boil. Cook the potatoes for 25 minutes or until fork tender.
Get the oven on: Preheat the oven to 190°C / 374°F and place the rack in the middle of the oven.
Drain: Pour the potatoes into a colander and drain the water out. Place the colander over the now dry pot that they cooked in and place the lid over the colander. It wont fit the pot tightly, that's fine. Leave them there for 5 minutes, it helps them steam finish.
Smash: Gently toss the potatoes onto the oven tray (sheet pan) and use either an egg lifter or fork to press down onto the potatoes. Remember the idea is to keep them smashed but in one piece so don't make mash! See notes below.
Season and add oil: Use your hands to smear (rub) the olive oil coating all the potatoes. Season well with salt and pepper, pour melted butter over and bake for 25 minutes or until fork tender.
Add bacon and cheese: Remove, add the bacon and cheese and bake for an additional 18 minutes or until the bacon is crispy and the cheese melted. Roughly a total of 45 minutes.
Grill/Broil: If you want them more brown and crispy, turn the grill / broiler on and put them under, move the tray to the top rack and grill for 2 minutes but watch them closely to not burn!
Garnish and serve: Serve warm with fresh chopped parsley and sea salt.