Warm German Potato Salad with Lentils and Mustard-Herb Dressing

Place 1000 g potato in a large pot and cover with 1500 ml water. Bring the pot to a boil over high heat, then reduce to a steady medium boil and cook for 18 to 22 minutes, until the potatoes are tender when pierced but not falling apart. Drain them well and let them sit for 5 minutes so excess steam escapes and the surfaces dry slightly. When cool enough to handle, cut the potatoes into thick bite-size slices so they stay intact in the salad.

In a second saucepan, combine 250 g green lentils with 900 ml water and bring to a boil over high heat. Lower the heat to medium-low and simmer for 20 to 25 minutes, until the lentils are tender but still hold their shape and do not split heavily. Drain thoroughly and set aside; the lentils should feel firm at the center but not chalky. Let them cool for a few minutes so they stay distinct when mixed into the warm salad.

Finely dice 180 g red onion. Heat 30 ml olive oil in a skillet over medium heat, then add the 180 g red onion and cook for 6 to 8 minutes, stirring often, until the onion turns glossy, soft, and lightly golden at the edges without browning deeply. The onion should smell sweet and mellow rather than sharp. Lower the heat slightly if it starts coloring too fast.

Add 80 ml apple cider vinegar, 35 g dijon mustard, 20 ml maple syrup, 8 g salt, 2 g black pepper, and 100 ml water to the skillet with the softened onion. Stir over medium-low heat for 1 to 2 minutes until the mustard dissolves fully and the dressing looks smooth, lightly thickened, and glossy. It should taste bright and assertive, with a balance of sharpness, sweetness, and salt. Do not boil it hard; a gentle simmer is enough to blend the flavors.

Transfer the sliced warm potato and the cooked green lentils to a large mixing bowl. Pour the hot dressing over the 1000 g potato and 250 g green lentils, then fold gently for 2 to 3 minutes so the slices stay mostly whole while the surfaces absorb the liquid. Let the mixture stand for 10 minutes, stirring once halfway through, until the potatoes look glossy and have soaked up much of the dressing. This resting step gives the salad its deep, seasoned flavor.

Thinly slice 250 g cucumber and 120 g radish, then finely chop 15 g dill and 20 g parsley. Keep the slices fairly thin so they blend into the salad without making it bulky, and chop the herbs small enough to distribute evenly. The cucumber should add cool snap, while the radish should bring a peppery bite. Have everything ready before the potatoes cool completely.

Add the 250 g cucumber, 120 g radish, 15 g dill, and 20 g parsley to the bowl with the dressed potato mixture. Fold everything together gently for 1 to 2 minutes until the herbs coat the potatoes and lentils and the fresh vegetables are evenly distributed. Let the salad rest for another 10 minutes before serving so the flavors settle and the temperature becomes pleasantly warm rather than hot. Serve when the salad looks glossy, well mixed, and aromatic, with the herbs still bright green.