Root veggie crumble

Name: Root veggie crumble
Cuisine: European, British
Ingredients: 2 medium carrots, cut into cubes; 2 medium beetroots, peeled and cut into cubes; 300g celeriac, peeled and cut into cubes; Drizzle of olive oil, for roasting; Salt; Pepper; 1 tbsp fennel seeds; 1 tbsp cumin seeds; 40g walnuts, roughly chopped; 40g pecans, roughly chopped; 40g rolled oats; 20g pumpkin seeds; 1 tbsp sesame seeds; 1 tsp smoked paprika; 1/2 tbsp ground coriander; 3 tbsp olive oil; 6 tbsp plain coconut yoghurt; Juice and zest of 2 lemons; 2 tbsp tahini; 1 tbsp extra virgin olive oil; 2 tbsp maple syrup