1 - Scrub the potatoes clean and place in a small saucepan with water and 1 tablespoon of salt.

2 - Bring to a boil and simmer the potatoes for about 10 minutes.

3 - Turn off the heat and let the potatoes stand in the water for 5 minutes.

4 - Drain the potatoes and allow to cool slightly.

5 - Remember that potatoes come in various sizes, so the cooking time may vary – if they do not easily glide off of a fork when speared and lifted out of the water, they are not done yet.

6 - Fry bacon slices and transfer to a dish lined with paper towels.

7 - Peel the red onion and slice in thin rings.

8 - Transfer the flour to a bowl and toss the onions in the flour.

9 - Remove onions and shake off excess flour.

10 - Heat the oil in a saucepan over medium heat.

11 - You can test whether the oil is hot enough by adding a small piece of onion to the saucepan.

12 - If the oil bubbles around the onion, the oil is ready.

13 - Transfer as many onion rings to the saucepan as can fit in one layer.

14 - Do not add too many onion rings at once.

15 - Fry the onions for a couple of minutes until they are golden brown.

16 - Transfer onions to a dish lined with paper towels and sprinkle with salt.

17 - Repeat the process until all onions are fried.

18 - Butter a slice of dark rye bread and arrange round potato slices (or, if the potatoes are very small, halved potatoes) on top.

19 - Top your open potato sandwich with a good mayonnaise, crispy fried onions, fried bacon and sliced chives.