In a small pot, place parsnips and onions, top with water and add seasoning; bring to a boil and cook until soft. Drain, reserving some of the cooking liquid, and place in a blender to purée, adding a bit of the reserved liquid. Add more liquid to get a nice smooth consistency. Set aside.
Lightly dust the shallot rings with flour. In a frying pan, add olive oil and sear shallot rings until golden and crispy. Set aside
In a small bowl, mix all ingredients; set aside.
Place scallops on a paper towel to remove moisture; remove the bit on the side of the scallop.
In a hot skillet, add olive oil and sear scallops for about 1 to 2 minutes on each side until scallop starts to split on the edges and brown, larger scallops may require more cooking time.
Spoon parsnip purée across the plate; place 3 seared scallops on top of the purée and top scallops with arugula and crispy shallot rings; drizzle with maple vinaigrette.
Tip: Cook scallops after all else is ready, to avoid them becoming tough.