How to Make It
Heat 1 tablespoon of the olive oil in a medium skillet. Add the minced garlic and cook over moderate heat, stirring occasionally, for 1 minute. Add the tomatoes and the bay leaf and cook over moderate heat until the sauce thickens, about 10 minutes. Stir in the thyme and rosemary and season with salt and pepper. Discard the bay leaf.
Meanwhile, heat 1 tablespoon of the oil in a medium skillet until the oil is shimmering. Season the lamb roast with salt and pepper and sear over high heat, turning occasionally, until well browned all over but very rare inside, 5 to 8 minutes. Transfer the lamb to a cutting board and let stand for at least 20 minutes or up to 45 minutes. Thinly slice the lamb.
Preheat the oven to 500°. Position 2 racks in the upper and lower thirds of the oven. Lightly oil 2 large baking sheets. On a lightly floured surface, roll or stretch out the Crispy Pizza Dough into four 8-inch rounds. Transfer the dough rounds to the prepared baking sheets. Brush the dough with the remaining 2 tablespoons of olive oil and spread the tomato sauce over the pizza crusts in a thin layer to within 1/2 inch of the edges. Bake the pizza crusts for 8 minutes, or until they are golden brown and almost cooked through.
Arrange the sliced lamb in a single layer over the pizza crusts. Scatter the sliced scallions and onion on top and season with salt and pepper. Spoon small dollops of the goat cheese all over the pizzas and drizzle lightly with olive oil.
Slide the pizzas directly onto the oven racks and bake for 1 to 2 minutes, or until the lamb is medium rare and the crusts are crisp. Transfer the lamb pizzas to plates. Mound the arugula on top, drizzle lightly with more olive oil and serve immediately.
Ask your butcher to bone the lamb rack or loin roast for you.