Pot Roast Beef With Roasted Vegetables - With greens

3 red onions , cut into 8 wedges 7 tablespoons extra virgin olive oil 1/4 cup balsamic vinegar 1 cup mayonnaise 1/4 cup chopped fresh basil 1 1/2 tablespoons[...]

1 lb roast beef , cooked (prime rib or any cooked leftover beef) 1 1/2 lbs cooked potatoes or 1 1/2 lbs mashed potatoes 5 shallots , peeled and julienne cut[...]

6 lbs beef chuck (at room temperature) 2 teaspoons chopped garlic 2 teaspoons McCormick's Montreal Brand steak seasoning (to taste) 1 teaspoon kosher salt 2[...]