In liquid measure, stir together honey, vinegar, 2 tsp (10 mL) of the horseradish and mustard. Slowly whisk in olive oil. Season with salt and pepper, to taste. Set aside.

Season steak with salt and pepper; place on greased grill over medium-high heat. Grill, covered, turning once, until medium-rare, about 4 minutes per side or until desired doneness. Remove to cutting board; spread remaining horseradish on each side. Let rest 10 minutes. Brush onion with some of the vegetable oil; place in grill basket. Grill, covered, turning once, until tender, 10 minutes. Brush both sides of bread with remaining vegetable oil. Grill until golden, about 1 minute per side. Thinly slice steak across the grain; coarsely chop onion. Cut bread into croutons.

On platter, place romaine, arugula, tomatoes, basil and onion. Drizzle with half of the dressing and toss. Top with steak and drizzle remaining dressing; toss. Sprinkle with croutons and cheese.

Tip:  If you like, toss tomatoes with 1/2 tsp (2 mL) of vegetable oil.  Place in grill basket; grill, covered, over medium heat, stirring occasionally, until lightly softened, about 5 minutes.