In a small skillet, heat 1 tablespoon olive oil (reserve the rest for cooking the crab cakes!), and add the minced bell pepper and shallot. Cook over low-medium heat for 10 minutes, stirring frequently. Don't let it burn, just brown it slowly. Do not skip this step!
Add the minced parsley, stir, and cook for another 1-2 minutes.
In a large bowl, combine the cooked pepper mixture with the rest of the crab cake ingredients, from the crab meat through the black pepper. Mix well. Form 4 crab cake patties with your hands (or make 8 small crab cakes).
Heat 1 tablespoon of olive oil in a large skillet, Carefully place the crab cakes on the skillet and cook for 4-5 minutes per side over low-medium heat, or until nicely browned. Remove from heat.
Make the mango relish
Combine all the ingredients for the mango relish in a small bowl and mix. Spoon the mango relish over the crab cakes to serve.
Notes
You can use finely minced shallot or diced scallion instead of a shallot, for both the crab cakes and the relish
You'll need finely minced red bell pepper, shallot/red onion/scallion, minced parsley, and lemon juice for both the crab cakes and the shallot, so prep enough for both at once.
If you want some spice, add some diced fresh jalapeno to the red pepper/shallot mixture in the crab cakes or to the mango relish.
You can use the same skillet for cooking the pepper/shallot mixture and the crab cakes - just use a large skillet in that case and wipe it clean in between in between.