In small saucepan, bring milk to simmer; add whole garlic cloves and simmer until tender, about 10 minutes. Remove garlic from milk; set milk and garlic aside.
Grease and flour 10-cup/2.5 L soufflé dish; set aside. Preheat oven to 425°F/220°C.
In saucepan, melt butter over medium-high heat; sauté carrots, salt, pepper and nutmeg until carrots are soft, 5 to 6 minutes. Stir in flour; cook, stirring, for 2 minutes. Stir in reserved milk; bring to boil. Reduce heat to medium; simmer, stirring, for 3 minutes. Scrape into large bowl. Whisk in egg yolks.
In separate bowl, beat egg whites with cream of tartar until stiff peaks form; fold one-third into carrot mixture. Fold in remaining whites. Scrape into prepared soufflé dish. Place on middle rack of oven; reduce heat to 400°F/200°C. Bake until puffed and golden, 25 to 30 minutes.
Parsley Sauce: Trim off long stems of parsley and discard. In pot of boiling salted water, blanch parsley for 30 seconds. Drain, chill under cold water and drain again. Using kitchen towel, press out any excess moisture. Chop parsley and add to small bowl of food processor; whirl with almonds, stock, salt and reserved poached garlic until fairly smooth, adding a little more stock if sauce is too thick. Stir in oil. Serve soufflé with sauce on the side.