Ham and Potato Pizza

Name: Ham and Potato Pizza
Ingredients: 3 tablespoons extra-virgin olive oil, divided, plus more for brushing; 2 pounds refrigerated pizza dough, at room temperature; 2 large cloves garlic, thinly sliced; 1 medium shallot, thinly sliced; 12 ounces fresh mozzarella cheese, roughly torn; 6 ounces thick-cut ham, chopped; 2 handfuls baby spinach; 12 ounces Yukon Gold potatoes (about 4 potatoes), cut into 1/8-in. slices; Kosher salt; Freshly ground black pepper; Ranch dressing, crushed red pepper, freshly grated Parmesan, and chopped flat-leaf parsley, for topping