In a large salad bowl, place the tomatoes and the butter lettuce. Add 1 to 2 tablespoons of shallot vinaigrette and mix gently well.
Place the salad on a serving plate and add the hardboiled egg, avocado slices and the crumble blue cheese. Add a touch of the vinaigrette in top of the egg.
Spread some of the blue cheese on the toasted French baguette and serve alongside.
Place all the ingredients in a blender and puree until all the shallot is gone. Taste and adjust the seasoning. If too thick or too pungent (shallot can be quite strong) add more oil to reach the wanted consistency and flavor.
This will make up to a cup of shallot vinaigrette. Can be stored in the refrigerator in an airtight container.