Boil the Potatoes with Baking Soda: Place unpeeled baby Yukon Gold potatoes in a large pot and cover with cold water by at least 1 inch. Add 1 tablespoon kosher salt and 1/2 teaspoon baking soda (alkaline water breaks down surface pectin to form a starchy mash layer that crisps like glass in the oven). Bring to a rolling boil over high heat, then reduce to medium-high and simmer for 15 to 18 minutes until a fork easily pierces through the center.

Drain and Steam Dry: Drain the potatoes thoroughly in a colander and let them sit in the hot pot off the heat for 5 minutes. Steam drying removes surface moisture, which is crucial for achieving shattering crispness rather than soggy steamed potatoes.

Smash the Potatoes: Preheat oven to 425°F (220°C) and generously brush a large heavy baking sheet with olive oil. Arrange the dry potatoes on the baking sheet 2 inches apart. Using the flat bottom of a heavy mason jar or glass tumbler, press down gently and firmly on each potato to crush it into a flat, craggy patty about 1/2-inch thick with shattered edges.

Brush with Garlic Herb Butter: In a small bowl, whisk together melted butter, olive oil, minced garlic, chopped rosemary, thyme, smoked paprika, salt, and black pepper. Generously brush the garlic herb mixture across the surface and into all crannies of the smashed potatoes.

First Roast: Transfer the baking sheet to the bottom rack of the oven and roast for 20 to 22 minutes until bottoms and edges are deeply golden and crispy.

Add Parmesan and Finish: Remove the sheet pan from the oven. Generously shower the tops and perimeter of each potato with freshly grated Parmesan cheese (spilling cheese onto the hot pan creates an irresistible lacy frico cheese skirt). Return to the oven on the upper rack for 8 to 10 minutes until the cheese is bubbling, lacy, and deeply caramelized. Sprinkle with fresh parsley and flaky Maldon sea salt; serve piping hot with garlic dipping sauce!