Toss sliced potatoes with olive oil, salt and pepper. Arrange in a single layer on a lined baking sheet. Cook for 10 mins, flip, and cook for a further 10-15 mins. If they need crisping up, a few minutes under the grill should do the trick.
Remove the potatoes from the oven and reduce the temperature to 200C.
Place half the potatoes on a separate baking sheet. Sprinkle with half the cheese, half the bacon, and a few jalapeno slices. Top with the remaining potato, followed by the remaining cheese, bacon, and a few jalapeno slices.
Garnish with spring onion and sour cream and serve with salsa.