Heat the oil in a medium saucepan over medium-high heat. Add the oregano, garlic and red pepper flakes and cook, stirring, until the garlic is golden brown, 1 to 2 minutes. Add the tomatoes, basil and 1/2 teaspoon salt and bring to a simmer. Reduce the heat to medium and simmer, with the saucepan loosely covered in foil to avoid splattering and stirring occasionally, until fairly thick, 5 to 10 minutes, depending on your tomatoes. Remove the basil.