Preheat your oven to 425°F.
Wash and chop the red bell pepper, zucchini, red onion, and tomato into bite-sized pieces.
On a baking sheet, toss the chopped vegetables with olive oil, salt, and pepper. Roast in the preheated oven for about 20 minutes until they are tender and slightly crispy along the edges.
While the vegetables are roasting, heat a skillet over medium-high heat. Add the lean beef mince and season lightly with salt and pepper. Cook until the beef is browned and cooked through, breaking it up into small crumbles as it cooks.
Once the beef is nearly done, push it to one side of the skillet and pour in the egg whites. Allow them to set slightly before gently stirring them into the beef, combining the flavors.
Combine the roasted vegetables with the beef and egg white mixture, stirring everything together until well distributed. Adjust seasoning with additional salt and pepper if needed.
Serve your savory skillet warm, enjoying the blend of crispy vegetables, savory beef, and light egg whites.