Place rack in center of oven, preheat oven to 400°F.
Place 3 lb. baking potatoes, peeled, cut into 1½" cubes, in a single layer in a 13x9" metal baking dish or roasting pan and pour ½ cup extra-virgin olive oil over.
Add 4 garlic cloves, finely chopped, 1½ tsp. dried oregano, crumbled, 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt, and freshly ground black pepper to taste and toss well to coat with oil.
Roast potatoes for 15 minutes.
Add ½ cup chicken stock and toss to combine; bake 10 minutes more.
Add ⅓ cup fresh lemon juice, toss again, and continue to bake until potatoes are fork tender, 10–15 minutes more.
Preheat broiler on high; broil potatoes until golden brown and turning crispy, 2–3 minutes.
Sprinkle with 2–3 Tbsp. chopped fresh oregano.
