For the candied pecans: Preheat the oven to 375 degrees F. Line a baking sheet with foil or a silicone mat.
Toss the chopped pecans with the maple syrup and spread out in 1 layer on the prepared baking sheet. Cook until fragrant and no longer tacky or sticky, about 12 minutes. Remove from the heat and sprinkle with a pinch of sea salt. Let cool before using.
For the challah French toast: Lower the oven temperature to 200 degrees F. Heat a griddle over medium-high heat.
In a medium bowl, beat together the milk, vanilla, cinnamon, nutmeg, salt and eggs. Dredge the challah slices in the batter.
Grease the griddle with the butter (about 1/2 tablespoon per slice). When the bubbles in the butter subside, add the dredged bread slices one at a time. Cook until beginning to brown, 2 to 3 minutes per side. Transfer to a baking sheet and keep warm in the oven.
For the sausage: Bring 4 cups water to a simmer in a pot. Poach the chicken sausages in the simmering water until cooked through, about 12 minutes. Remove the sausages and split them down the middle lengthwise so they are hinged like a book.
Heat a cast-iron skillet over medium-high heat. Add the butter to the skillet and brown the sausages on both sides to give them some color. Add the diced apples along with the cinnamon and cook until the apples are just tender. Remove the skillet from the heat and keep warm.
For the maple cream icing: In a food processor, combine the cream cheese, butter, confectioners' sugar, maple syrup and vanilla extract. Add the milk and process to make a thickish glaze that can still be drizzled. Transfer to a bowl and set aside.
For the eggs: Fill a skillet with water and bring to a simmer. Add the vinegar. Crack each of the eggs into a small bowl. Carefully drop the eggs one by one into the water and allow the water to return to a simmer. Cover with a lid and turn off the flame. Let sit for 4 minutes for a runny egg or longer for desired doneness. Remove the eggs from the water using a slotted spoon. (If not using immediately, transfer them to an ice bath to hold until serving.)
The build: Lay a piece of cooked challah French toast down like a hot dog bun. Add 1 tablespoon of the maple cream icing and spread. Add a chicken sausage and some apples, another tablespoon of the icing and a poached egg. Sprinkle 1 tablespoon of the candied pecans over top. Repeat with the remaining ingredients. Serve immediately.