Drain the lump crab meat thoroughly and pick through it to remove any remaining shell fragments.
In a medium mixing bowl, whisk together the egg, 2 tablespoons of the Greek yogurt, Dijon mustard, Old Bay seasoning, chopped parsley, sea salt, and black pepper.
Gently fold in the lump crab meat and the almond flour until just combined, being careful not to over-mix and break up the crab lumps.
Form the mixture into 2 or 3 thick patties and place them on a plate; refrigerate for 10 minutes to help them set.
While the cakes chill, prepare the aioli by whisking the remaining 2 tablespoons of Greek yogurt with the lemon juice and lemon zest in a small bowl.
Heat the olive oil in a non-stick skillet over medium-high heat.
Carefully place the crab cakes in the hot skillet and sear for 4 to 5 minutes per side until a deep golden brown crust forms.
Serve the hot crab cakes immediately with a dollop of the lemon aioli on top.