Cook the potatoes in a pot with cold water. Once done, drain and allow to cool.
Thickly slice the potatoes and set aside.
Slice the tomatoes and then cut them into triangles.
Put the mayonnaise and blueberries in a blender with a teaspoon of lemon and blend until the blueberries are properly mixed with the mayonnaise.
Place the mayonnaise over the sliced potatoes and then add a tomato on top.