Loaded Scandi Hot Dogs

Ingredients

• 500 g potatoes
• 125 g whole-egg mayonnaise
• 1 tsp dijon mustard
• ¼ brown onion, finely chopped
• 1 tbsp finely chopped capers
• 1 tbsp finely chopped gherkin (dill pickle)
• 1 tbsp freshly chopped chives
• ½ tsp mild curry powder
• 1 tbsp fresh lemon juice
• ¼ tsp sugar
• ¼ tsp freshly cracked black pepper
• ¼ tsp sea salt flakes, or to taste
• 4 bamboo skewers
• 4 good-quality frankfurt sausages – continental-style, not the red type
• 4 hot dog brioche rolls
• 4 tbsp tomato ketchup
• 4 tbsp American mustard
• Crispy fried shallots