A fast beef stir-fry with crisp snow peas is the Monday high protein dinner that proves starting the week healthy doesn't mean eating boring food.
Slice the beef sirloin thinly against the grain for tenderness; toss with cornstarch and black pepper for an even coating.
Heat canola oil in a large skillet or wok over high heat; add the beef in a single layer and sear for 1 minute until well-browned, then remove to a plate.
Reduce heat to medium-high and add sliced onion, minced garlic, and red bell pepper; stir-fry for 2 minutes until fragrant and slightly softened.
Add snow peas and continue stir-frying for 1–2 minutes, maintaining crisp texture—do not overcook.
Return beef to the pan; add soy sauce and sesame oil, tossing all ingredients quickly over medium-high heat for 1 minute until sauce coats and beef is heated through. Serve immediately.