Fill a medium saucepan with water and add the white vinegar; bring to a gentle simmer over medium heat.
In a small skillet over medium heat, lightly sauté the baby spinach until wilted, then set aside.
In the same skillet, lightly brown the Canadian bacon slices for 1-2 minutes per side until heated through.
Toast the whole grain English muffin halves until golden and crisp.
Prepare the hollandaise by whisking the egg yolk, Greek yogurt, lemon juice, sea salt, black pepper, and cayenne in a small heat-safe bowl.
Place the bowl over the simmering water, ensuring the bottom does not touch the liquid, and whisk constantly while slowly adding the melted ghee until the sauce is velvety and thickened.
Carefully crack each egg into a small ramekin and slide them into the simmering water; poach for 3-4 minutes until the whites are set but yolks remain runny.
To assemble, place the toasted muffin halves on a plate, top with the sautéed spinach, followed by the Canadian bacon and the poached eggs.
Drizzle the warm yogurt hollandaise over the eggs and serve immediately.