Golden Beet and Lentil Salad with Feta

The beets and mint for this salad arrived together in my vegetable box. There are always lentils in my pantry and, as luck would have it, there was feta in the fridge, so dinner more or less assembled itself from there.
The beets and lentils are both dressed while they are still warm, which gives them a chance to absorb a punchy Dijon and red wine vinegar dressing. Piled onto a plate while still warm and topped with cool, salty feta and plenty of fresh mint, this was a very simple combination, but the earthy lentils and sweet golden beets were truly tasty against the sharp mustard dressing, and the feta and mint provide just enough contrast to keep things interesting (something which is really important when the salad one is eating is one's meal and not a side dish.)
This is best eaten straight away, while the beets and lentils are still warm and the feta and mint are cool and fresh.
2 small golden beets
1/4 cup Puy lentils
1 Tbsp red wine vinegar
2 Tbsps olive oil
2 tsps Dijon mustard
1 bay leaf
2 Tbsps crumbled feta
1 Tbsp chopped mint
Pinch of salt
Preheat the oven to 425.
Put the beets on a sheet of aluminum foil, add 1 Tbsp water and seal the foil tightly around them to make a packet. Roast for about 40 to 45 minutes, until the beets are completely tender and easily pierced with a knife.
Meanwhile, put the lentils and bay leaf in a small saucepan and cover generously with water. Bring to a boil, reduce to a simmer and cook for about 18 to 22 minutes, until the lentils are tender but still holding their shape. Drain well and discard the bay leaf.
While everything is cooking, whisk together the red wine vinegar, olive oil, Dijon mustard, a splash of water and a pinch of salt in a large bowl. The dressing should be quite punchy.
As soon as the lentils are drained, put them into the bowl containing the dressing and toss to combine while they are still warm.
When the beets are cool enough to handle, peel them and cut them into cubes. Toss them with the lentils and the dressing.
Pile the warm beet and lentil mixture onto a plate and scatter the feta and chopped mint over the top.