Peel and chop the carrots, potato, and onions into roughly equal pieces.

Juice half of the orange; reserve the remaining juice for finishing the soup.

Cook the chopped carrots, potato, and onions in the large pot over medium-high heat until lightly browned.

Dissolve the miso paste in 1.5 l water, then pour it into the pot until the vegetables are covered.

Add the paprika, turmeric, salt, and orange juice; stir the soup well.

Simmer the soup for at least 45 minutes, until all vegetables are very tender.

Mash the canned mackerel with the cream cheese and most of the chopped chives until spreadable.

Sear the cherry tomatoes in a hot frying pan with the za'atar until softened and lightly blistered.

Blend the cooked vegetables and broth until completely smooth and velvety.

Spread the mackerel mixture over the whole grain bread and top with the seared cherry tomatoes.

Serve the soup with the toasts; garnish the soup with remaining chives and smoked salt.