Heat oil in a wide saucepan over medium-high heat, add shallot and garlic and stir occasionally until just tender (2-3 minutes), then add bacon and fry until golden (5-7 minutes). Deglaze pan with wine and reduce by half (1-2 minutes). Add peas and stock and simmer until peas are tender (3-4 minutes). Add lettuce on top, season to taste, cover and cook until lettuce wilts (2 minutes). Add butter, stir to combine and serve.