Preparation: 20 minutes - Cooking: 2-3 minutes
2 onions, peeled and cut into thin slices
1 tsp olive oil
1 1/2 tsp sugar
1/2 tsp ketchup (plus some extra for serving)
4 Frankfurt sausages
4 hot dog buns
We prepare the onions. Put onions in a saucepan and add as much water as to cover and place over medium heat. When the water has almost evaporated, add the oil. Mix for 1 minute and add the sugar and 1/2 tsp ketchup. Stir until the sugar has dissolved and remove from fire.
Place the sausages in a pot with enough water. Boil over medium-high heat for about 2-3 minutes (counting from the boiling point). Remove from heat and place them on a kitchen towel to dry.
Open buns alongside without cutting completely. Spread with ketchup, put one sausage in each one and top with caramelized onions. Spread some mustard and serve.