Chef John's Brazilian Cheese Bread (Pao de Queijo)

Ingredients (8)

• ✓ 2 ¼ cups tapioca flour, or more as needed
• + ⅔ cup milk add to pantry
• + ½ cup mild olive oil add to pantry
• + 1 teaspoon kosher salt add to pantry
• + 2 ounces freshly grated mozzarella cheese add to pantry
• + 2 ounces finely grated Parmigiano-Reggiano cheese add to pantry
• + 2 large eggs, beaten add to pantry
• + 1 pinch cayenne pepper add to pantry