Cook cauliflower in salted boiling water until tender, 4–6 minutes. Drain and transfer to a food processor. Add goat cheese, lemon oil, 3 eggs, salt, and pepper; purée until smooth. Transfer to a large bowl; chill until ready to use. Whip egg whites into stiff peaks in a bowl; in batches, fold whites into cauliflower purée and divide between prepared ramekins. Bake until golden and puffed, about 30 minutes.