Wintry vegetable crumbles

Name: Wintry vegetable crumbles
Ingredients: 400ml vegetable stock; 450g celeriac, peeled and diced; 3 carrots, peeled and diced; 3 small sweet potatoes, peeled and diced; 2 leeks, sliced; 200ml tub crème fraîche; 2 tbsp plain flour; 1 tbsp wholegrain mustard; 1 tsp thyme leaves; 50g butter, diced; 50g plain flour; 50g ground almond; 50g parmesan, grated; 25g flaked almonds