Prepare the Steak:
Season both sides of the steaks with salt and pepper.
Sear the Steak:
Heat olive oil in a large skillet over medium-high heat. Sear the steaks for 1–2 minutes per side, until browned. Remove from the skillet and set aside.
Cook the Aromatics:
In the same skillet, reduce the heat to medium and add the onions. Sauté until softened, about 5 minutes. Add the minced garlic and cook for another 30 seconds, stirring constantly.
Build the Sauce:
Pour in the crushed tomatoes and broth. Stir in the oregano and red pepper flakes (if using). Simmer the sauce for 5–7 minutes to allow the flavors to meld.
Return the Steak to the Pan:
Lower the heat and nestle the seared steaks into the tomato sauce. Cover and simmer for 8–10 minutes, or until the steak is tender and cooked to your liking.
Adjust Seasoning:
Taste the sauce and adjust the seasoning with additional salt or pepper as needed.
Serve:
Transfer the steaks to a serving plate, spoon the sauce over the top, and garnish with fresh basil leaves.