Seal green beans in a bag with two pats of butter and lemon juice. Sous vide for an hour. Green beans benefit a lot from cooking sous vide - they will retain their color, vibrancy, flavor and texture.
In a small bowl, thoroughly mix honey, mustard, shallots, olive oil and champagne vinegar. Remove green beans from water bath, drain and plate. Top with dates, almonds, vinaigrette and garnish with lemon zest and cracked pepper.