French Onion Soup

With decadently cheesy toast.

4 onions 30g butter 3 Tbsp extra virgin olive oil 8 sprigs thyme 2 bay leaves 1 tsp salt 1 Tbsp sugar 1 Tbsp apple cider vinegar ¾ cup white wine 4 cups beef stock freshly ground black pepper 50g goat’s cheese 50g mature cheddar 1 Tbsp Dijon mustard small handful parsley 4 slices ciabatta bread