In a large saucepan, place potatoes in a single layer covered with 1" of water. Bring to a boil over high heat. Reduce to a simmer, cooking for a total of 30 minutes. Potatoes are done when they can easily be pierced with a knife or fork but not fall apart.
Preheat oven to 450°F. Prepare a baking sheet with parchment paper.
Remove potatoes from heat. Using a slotted spoon, drain one potato. Transfer to a clean kitchen towel. Fold towel over and press down firmly to 'smash' the potato. Transfer to your prepared baking sheet. Repeat process with remaining potatoes.
Drizzle olive oil over potatoes. Sprinkle with remaining 3/4 tsp salt and optional sprinklings of ground pepper and red pepper flakes.
Bake for 30-40 minutes, flipping carefully half way through.