Preheat the oven to 375˚F (190˚C). Line a baking sheet with parchment paper.
Rub the steak with 2 tablespoons of olive oil, the Jazzy Seasoning, and 1 teaspoon salt. Let marinate in the refrigerator until ready to grill.
In a medium bowl, toss together the remaining 2 tablespoons olive oil, the garlic, green beans, tomatoes, bell peppers, and remaining 1 teaspoon of salt. Spread the vegetables on the prepared baking sheet and bake for 15 minutes, until the tomatoes are just beginning to burst.
Add the sliced shallot to a medium bowl. Sift the cornstarch over the shallots and toss to coat.
Heat 2 inches of oil in a large skillet until it reaches 350˚F (180˚C).
Working in batches, fry the shallots for 2 minutes, flipping halfway through, until golden brown. Transfer to a paper towel-lined plate to drain and season with salt.
Heat a griddle pan over medium-high heat. Sear the steak for 2 to 3 minutes on each side, depending on thickness, until medium-rare or cooked to your desired temperature. Let rest while you prepare the dressing, then slice.
To make the dressing, mix together the yogurt, sour cream, lemon juice, Jazzy Seasoning, mustard, salt, and pepper in a medium bowl.
To assemble the salad, toss the roasted vegetables with the lettuce in a large bowl. Top with the sliced steak and fried shallots. Drizzle with the dressing. Divide between bowls and serve with more dressing on the side.