Add the peas to a bowl and let sit to thaw while you prepare the rest of the salad.
Cook the Bacon
Cut the bacon into lardons and add to a skillet and cook until crispy. Remove from pan to paper towel-lined plate. Set aside.
Prepare the Veggies
While the bacon is cooking, prepare the veggies. Tear the lettuce into small pieces and place in a large bowl. Slice the mushrooms, grate the carrot, and slice the green onions and place in separate prep bowls. Slice a lemon in half and squeeze the juice out of one half into a small bowl. Set aside.
Make the Sauce
While the bacon is cooling, add all the sauce ingredients to a small bowl and mix well with a whisk. Set aside.
Layer and Top the Salad
Season the lettuce with kosher salt and pepper and mix together to blend. Add the veggies and other ingredients in this order: mushrooms, carrots, bacon, peas, green onions. Add as much or as little of each as you would like.
Add the the sauce to the top of the salad, distributing as even as possible. Using a spatula, spread the sauce around the top of the salad, from edge to edge, covering the entire salad top. You will see some of the salad poking through and that is okay. Garnish with green onions and dill is desired. You can also add a bit of the bacon as garnish.
Put a lid on the bowl, or cover with plastic wrap and refrigerate for at least 2 hours, preferably 24 hours.
Serving the Salad
Gently mix the salad and dressing to together to combine. Transfer to a serving bowl or use the bowl it is in for serving. Enjoy!