Trim and clean the scallions: discard root ends and any wilted dark green tips. Using a sharp knife, thinly slice the white and pale green parts (about 1/8-inch rounds). Reserve the darker green tops and slice them thin for a milder, brighter garnish. Finely slice the chives. Mince or very finely grate the garlic clove.

Soften and combine base

Place the softened cream cheese, softened butter and sour cream in a medium mixing bowl. Using a rubber spatula or electric hand mixer (low speed), blend until smooth and homogenous, scraping the bowl so no lumps remain. The mixture should be spreadable but still slightly thick.

Fold in scallions and seasonings

Add the sliced scallion whites and pale greens, sliced chives, grated garlic, lemon juice, kosher salt and freshly ground black pepper to the cream cheese base. Gently fold everything together with a spatula until evenly distributed. Taste and adjust seasoning, adding additional salt, pepper or lemon juice as desired. If using, fold in the optional smoked paprika or Aleppo pepper for a touch of warmth and color.

Texture and chill

If you prefer a slightly lighter texture, beat the mixture 10–15 seconds with the electric mixer on low after folding, then scrape down the sides. Transfer the shmear to a small serving bowl or container, smoothing the top with a spatula. Cover and chill in the refrigerator for at least 30 minutes to allow flavors to meld and for the scallions to soften slightly. (You can refrigerate up to 24 hours.)

Finish and serve

Just before serving, taste and adjust seasoning. Drizzle the top with the optional teaspoon of extra-virgin olive oil and sprinkle the reserved darker scallion tops and an extra pinch of chives for color. Serve at slightly chilled or near-room temperature with bagels, toasted bread, fresh vegetables, or smoked fish.