Cut the bacon into strips 5-6mm (¼") thick across the width of the rasher.
Cut the shallots in half lengthways, then peel them and trim the root end.
Finely slice the garlic cloves.
Remove the outer leaves from the lettuce, trim the base, then slice each lettuce in half lengthways.
Run the peas under cold water to defrost them.
Heat a 30cm or 12" frying pan or skillet (non-stick) over a high-medium heat, and when hot, add the bacon and cook for 2-3 minutes, or until it starts to become golden at the edges.
Add the butter and garlic, cook for 1 minute, then push the ingredients to the side and place.
Add the shallots, cut-side down and cook for 3-5 minutes. Do not move the shallots during this time!Once the onions have caramelised on the cut side, push them to the side of the pan with the bacon.
Place the lettuce cut-side down in the centre of the pan. Cook for 3-4 minutes, until it starts to take on some colour.
Pour the chicken stock into the pan and reduce the heat to medium-low. Flip over the lettuce, stir everything together, and cook for 2-3 minutes.
Add the peas, cream and black pepper and cook for a final minute or two over a medium-high heat before serving.