Heat your oven to 200C/180C Fan.
Peel the squash, halve lengthways, de-seed then cut into roughly 1cm slices.
Put onto a roasting tray and toss with a good drizzle of neutral oil and the whole cumin, coriander, mustard seeds & some seasoning.
Spread into a single layer so that the squash roasts evenly, bang in the oven for 35-40 minutes until tender and a little caramelised.
Meanwhile, rinse the lentils then tip into your largest saucepan.
Finely grate in 2 of the garlic cloves and half the ginger, add the turmeric, 1 ½ tsp of the ground cumin and a big pinch of salt then top up with 1.4 litres of cold water.
Bring to the boil, then bubble away, stirring occasionally for 25-30 minutes until the lentils are completely cooked.
While the dal is doing its thing quick pickle your onion.
Very finely slice, put into a bowl, juice in one of the limes, add a big pinch of salt then use your fingers to scrunch the onion into the juice - this encourages it to soften.
Set to one side.
Pick most of the mint leaves, add to a food processor or blender.
Peel and roughly chop the remaining ginger and green chilli, add this too, along with the remaining peeled garlic clove, ½ tsp ground cumin and juice of 1 lime.
Blitz until super finely chopped then stir through the yogurt and season to taste.
Roughly chop the nuts if using.
Season up your cooked dal then ladle into bowls, top with the roasted squash, pickled onions, that mint yogurt, roasted nuts (if using) and finally a few more mint leaves.
