Can't find broccolini? Broccoli will work just as well.
Preheat the broiler. On 2 baking sheets lined with foil, divide the broccolini. Drizzle with the oil. Season with salt and pepper. Working with 1 sheet at a time (if needed), broil, rotating the sheet halfway through cooking, until the broccolini is crisp-tender and charred in spots, 7 to 8 minutes.
Meanwhile, in a large skillet, melt the butter over medium heat. Cook, stirring often, until it stops foaming and turns golden brown, 3 to 5 minutes. Add the almonds, preserved lemon peel, and lemon juice; season. Cook until heated through, about 1 minute.
Arrange the broccolini on a platter. Top with the brown butter and almonds.