Heat the oven to 425°. Place the carrots in a large bowl and toss with 2 tablespoons olive oil and a sprinkle of salt. Spread on a rimmed sheet pan and place in the oven, cut-side down. Roast for 20-25 minutes, until the carrots are softened and browned in spots.
While the carrots are roasting, make the pesto. Set aside ¼ cup of parsley leaves, then roughly chop the remaining leaves and stems and combine in the bowl of a food processor with ½ cup pumpkin seeds, garlic, 1 tablespoon lemon juice, 1 teaspoon of zest, and a sprinkle of salt. Pulse to get everything roughly chopped. Stream in the remaining ½ cup olive oil and continue pulsing to make a slightly chunky pesto. Taste and adjust seasoning.
Arrange the carrots on a platter and spoon pesto over the top. Sprinkle with some remaining lemon juice, breadcrumbs, some of the remaining pumpkin seeds, reserved parsley leaves, and lemon zest. Finish with an extra sprinkle of salt. Serve warm or at room temperature.