Step 1

Bring 1 cup water and ½ teaspoon salt to boil in large saucepan over high heat. Add broccoli stalks, then place florets on top of stalks so they sit just above water. Cover and cook until broccoli is bright green and crisp-tender, about 3 minutes. Meanwhile, fill large bowl halfway with ice and water. Drain broccoli well; transfer to ice bath; and let sit until just cool, about 2 minutes. Transfer broccoli to triple layer of paper towels and dry well. Empty and dry bowl and set aside.

Step 2

Process avocado, oil, lemon zest and juice, garlic, pepper, and remaining ¾ teaspoon salt in food processor until smooth, about 30 seconds, scraping down sides of bowl as needed. Season with salt and pepper to taste.

Step 3

Toss broccoli, dressing, cranberries, almonds, shallot, and tarragon in now-empty large bowl until evenly coated. Season with salt and pepper to taste. Serve.