Preheat the oven to 425 degrees. Place the trimmed carrots on a sheet pan, and drizzle with 1 tablespoon olive oil and sprinkle with 1/2 teaspoon coarse salt. Roast the carrots, shaking the pan to roll them around a bit at the halfway mark, for a total of 30 minutes. When the tips are darkened and the carrots are very soft when pierced with a paring knife, they are done. If using thicker carrots, peel and slice lengthwise in quarters to make thin strips, and proceed.
To make the sauce: While the carrots roast, peel and slice the reserved half bunch of carrots. It should make about 1 cup of sliced carrots.
Set up a steamer and bring the water to a boil, and place the sliced carrots and 1/4 cup toasted almonds in the steamer. Put the steamer in the pot, cover and cook for 10 minutes. Take the steamer out and let cool slightly.
Place the steamed carrots in a food processor or blender. In the food processor, process the carrots and almonds and scrape down several times to mince finely. Gradually add the milk with the machine running, and scrape down until smooth. Add the orange juice, cayenne and 1/4 teaspoon salt, and process until very creamy. If using a blender, add all the sauce ingredients and process until smooth.
Put the sauce in a small saucepan to heat just before serving.
To make the gremolata: Finely mince the carrot tops or parsley leaves. Add the remaining almonds and lemon zest to the pile of minced leaves and finely chop, mincing it all together. Place mixture in a small bowl and stir in 1 tablespoon olive oil and remaining 1/4 teaspoon of salt.
