Preheat grill pan or grill to medium high heat. If using a charcoal grill, prepare coals.
Combine ground sirloin with wine, thyme, shallot, steak seasoning or salt and pepper. Form meat into 4 large patties, 1 to 1 1/2-inch thick. Drizzle patties with extra-virgin olive oil to keep them from sticking to grill or grill pan. Cook patties 5 minutes on each side for medium rare, 8 minutes on each side for medium well.
Toast rolls under hot broiler or in toaster oven. Spread mousse pate on the bun bottom. Top with burger, cornichons and red leaf lettuce. Spread bun tops with grainy mustard and set into place.
Place greens and scallions in a medium bowl. Whisk tarragon, mustard and vinegar together and add oil in a slow stream. Pour dressing on greens and toss with tongs. Season salad with salt and pepper, to taste.
Serve burgers with greens and Portobello Mushroom "Fries".
Yield: 4 servings
Prep time: 10 minutes
Cook time: 10 to 16 minutes
Ease of preparation: easy
Portobello Mushroom "Fries":
4 large portobello mushroom caps
Extra-virgin olive oil, for drizzling, plus 1/4 cup
Steak seasoning blend, such as Montreal Steak Seasoning, or coarse salt and black pepper
2 eggs, beaten
1/4 cup flat-leaf parsley, chopped
1 cup Italian bread crumbs
1/2 cup shredded or grated Parmesan
Preheat a grill pan over medium high to high heat.
Scrape the gills off the underside of portobello mushroom caps with a spoon. Brush caps gently with a damp cloth to clean them. Drizzle caps with oil to keep them from sticking to the grill pan and season the caps with steak seasoning or salt and black pepper.
Grill mushrooms 3 or 4 minutes on each side under a loose tin foil tent until just tender. Remove from heat and cool 5 minutes.
Slice grilled caps into 1/2-inch strips. Turn strips in egg, then coat in mixture of parsley, bread crumbs and cheese. Cook "fries" over medium high heat in enough extra-virgin olive oil to coat a nonstick skillet in a thin layer, about 1/4 cup. "Fries" will brown in 2 or 3 minutes on each side.