1. Heat oil in 12-inch skillet over medium-high heat until shimmering. Add leek and cook, stirring frequently, 3 to 5 minutes (leek should be softened). Add garlic and cook, stirring frequently, until fragrant, about 30 seconds.

2. Stir in peas, cream, and sugar. Cover and cook until peas are bright green and just heated through, 3 to 5 minutes. Add tarragon and butter and toss until incorporated. Remove pan from heat; stir in vinegar. Season with salt and pepper; serve immediately.

Serves 4