Preheat a skillet over medium heat then pour olive oil into it.
Once the oil is hot, put the tuna into the skillet and fry until the tuna is lightly golden brown.
Remove the tuna from the skillet then set aside.
Next, stir in chopped onion and sauté until lightly golden brown and aromatic.
After that, pour tomato puree into the skillet and season with pepper and oregano.
Bring to a simmer then add fried tuna to the skillet.
In the meantime, preheat a saucepan over medium heat then add almond butter to the saucepan.
Stir in broccoli florets and cauliflower florets to the saucepan then sauté until aromatic. Cook until the vegetables are tender but still crunchy.
Transfer the tuna to a serving dish together with the gravy and serve with sautéed broccoli and cauliflower.
Enjoy!