Heat oil in a large saucepan over medium-high heat. Add the onion and cook, stirring occasionally, for about 3 minutes or until the onion starts to soften.
Next, add the diced green pepper and cook for about 3 minutes more.
Add the garlic and sauté for 1 minute longer, stirring constantly.
Add the ground beef to the pan. Break it up with a wooden spoon as it starts to cook. Brown until the meat is almost fully cooked (about 5-8 minutes or so).
Add the tomato sauce, tomato paste, salt, pepper, red pepper flakes, and frozen corn. Bring to a low boil, then reduce to a simmer over low heat. Cover and let the sauce simmer for 10 minutes, stirring at the 5-minute mark. At the very last minute, stir in the fresh basil.
Serve hot goulash over baked potatoes, mashed potatoes, steamed potatoes, or cooked pasta.
If desired, fill a sandwich-size zip-top bag with about 1/3-1/2 cup of sour cream. Squish the sour cream into one corner of the bag. Snip that corner of the bag off with a pair of kitchen scissors and pipe little sour cream ghosts, about 1 1/2 tablespoons each, onto each serving of goulash. Arrange two olive slices on each ghost to look like eyes!