Increase the oven temperature to 450°F. Drain the potatoes and transfer them to a bowl of ice water for a couple of minutes. Once cool, transfer the potatoes to paper towels and let fully dry. Use your hands or a measuring cup to smash the potatoes flat. Transfer them to the sheet pan in the bacon fat. Drizzle olive oil over top to coat them well. Season with a generous pinch of salt. Roast the potatoes for about 20-25 minutes until crisp, flipping halfway through.