1. Steak Spice: In spice grinder or with mortar and pestle, finely grind peppercorns, mustard seeds, coriander seeds and dill seeds. Stir in salt, garlic powder, onion powder, sugar and smoked paprika.
2. Garlic Aioli: Stir together mayonnaise, olive oil, parsley, lemon juice, mustard, garlic, salt and pepper; refrigerate until ready to use.
3. Grilled Steak Platter: Preheat XL Smokeless Grill. Rub each steak with 1/2 tsp oil and spice mixture. Grill steaks, turning once, for 8 to 10 minutes for medium-rare or until desired doneness. Let rest for 10 minutes.
4. Meanwhile, toss together asparagus, onion, 1 tbsp oil, and 1/4 tsp each salt and pepper; grill for 6 to 8 minutes or until grill-marked and tender. Brush mushrooms with remaining oil, salt and pepper; grill, stem side up, for 3 to 4 minutes per side or until well-marked and tender.
5. Slice steaks and mushrooms; arrange on large board or platter. Add grilled asparagus and onion rounds. Sprinkle with goat cheese. Serve with baguette slices and aioli.