Preheat oven to 200°C/400°F. Line a baking sheet with parchment paper.
Add the diced butternut squash and the chopped red peppers to the baking sheet. Sprinkle with the chilli flakes, drizzle with 1 tablespoon of the oil and add a good pinch of salt and pepper. Toss with your hands to coat. Roast in the preheated oven for 25-30 minutes until everything is tender and a little charred at the edges.
Whilst the vegetables are roasting, heat the remaining tablespoon of olive oil in a large saucepan over medium high heat. Once hot, add in the onion and saute for 5 minutes or until softened.
Add the garlic and spices and continue to cook, stirring, for 30 seconds.
Add the red lentils to the pot and give them a good stir to coat in the onions and spices. Next, pour in the stock and bring to the boil.
Reduce the heat to a simmer and add the roasted vegetables. Continue to simmer for 15 minutes until the lentils are soft.
Carefully transfer everything into a blender and blend until smooth. Take care to cover the top of the blender with a tea towel to avoid any splashes and start blending slowly, gradually increasing the speed until smooth.
Season to taste and serve topped with a little yoghurt and thyme leaves, if liked. See notes section below for suggested instructions on how to make some tasty little cheesy toasts for dipping.