Roast the tomatoes: Heat the oven to 400 degrees. In a small bowl, combine the cherry tomatoes, olive oil, Aleppo pepper, salt, coriander, black pepper, fennel and cloves and toss to coat. Transfer to a small ovenproof dish, ideally in a single layer, and roast, stirring as needed to avoid burning, until the tomatoes are blistered but maintain some structure, 15 to 20 minutes.
Let the tomatoes cool to room temperature, then toss to coat in the spices and oil from the bottom of the pan — you want all of the juices. Transfer to a small bowl, add the vinegar and pomegranate molasses, and mix to combine.
Supreme the grapefruit: Cut the peel and white pith away from the grapefruit with a sharp knife, then cut segments away from between the membranes around the core. Squeeze the juice from the core into the bowl with the segments and discard the squeezed-out bits. (You can spoon a little of the juice along with the segments to the final dish, or enjoy a little invigorating behind-the-scenes shot of grapefruit juice.)
Spoon the marinated feta onto a serving dish. Arrange the roasted tomatoes (and any accumulated juices) and the grapefruit segments over the feta, and top with the tarragon.
