Preheat oven to 375 degrees Fahrenheit
Sauté onion with olive oil, until tender and translucent.
Thinly slice tomato, set aside.
Whisk egg in a small bowl, set aside.
Roll out the pie crust onto a parchment paper lined baking sheet.
Spoon the sauteed onions in the middle of the crust.
Top with sliced tomato, corn and a dash of salt & pepper.
Fold up the edges of the pie crust around the ingredients.
Brush the egg wash on the folded edges.
Bake at 375 degrees F for approximately 20-25 minutes or until the crust is golden brown.
Remove from the oven and let cool. Garnish with fresh parsley and blue cheese crumbles, if desired.