Brennans Eggs Hussarde

Name: Brennan’s Eggs Hussarde
Ingredients: 2 cups plus 3 tbsp. unsalted butter; 1 clove garlic, finely chopped; 1 scallion, finely chopped; 1⁄4 yellow onion, finely chopped; 1⁄4 cup finely chopped ham; 1⁄4 cup minced mushrooms; 1 tbsp. flour; 3⁄4 cup beef stock; 1⁄4 cup dry red wine; 2 tsp. Worcestershire sauce; 1⁄2 tsp. dried thyme; 1 bay leaf; 1⁄4 cup finely chopped parsley; Kosher salt and freshly ground black pepper, to taste; 4 egg yolks, plus 8 poached eggs, for serving; 1 1⁄2 tsp. red wine vinegar; 1⁄4 tsp. cayenne pepper, plus more for serving; 1 medium tomato, cut into 4 slices; 1⁄3 cup grated Parmesan cheese; 8 slices Canadian bacon; 8 Holland rusks