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-high heat, sear the lean sliced ham for 1-2 minutes per side until the edges are golden and crispy.
Toast the whole grain English muffin halves in a toaster or under a broiler until they are lightly browned and firm.
Crack each whole egg into a small ramekin, then gently slide them into the simmering vinegar water to poach for 3 minutes until the whites are opaque and set.
In a small heat-proof bowl set over a pot of barely simmering water, whisk the egg yolk, ghee, Greek yogurt, and lemon juice constantly until the mixture thickens into a velvety sauce.
Remove the sauce from the heat and whisk in the sea salt, black pepper, and cayenne pepper.
Place the toasted muffin halves on a plate and layer each with a handful of fresh baby spinach and two slices of the crispy ham.
Carefully lift the poached eggs from the water with a slotted spoon, pat dry with a paper towel, and place them atop the ham.
Drizzle the warm yogurt-hollandaise sauce generously over the eggs and serve immediately.