For the Sally Lunn bread: Butter and spray a 10-inch (14-cup) tube pan well and set aside. Put the milk in a measuring cup, add the yeast and pinch of sugar and mix to combine. Let proof for 5 minutes. Stir together the warm water and baking soda in another measuring cup or small bowl.
Stir together the flour, salt and 1/3 cup sugar in the bowl of a stand mixer fitted with the hook attachment. Stir in the eggs on medium speed until the dough starts to come together. Add the yeast mixture, baking soda mixture and melted butter and mix on medium to medium-high until the batter comes together and is smooth. The dough will be soft and slightly sticky.
Preheat the oven to 400 degrees F. Spoon the batter into the tube pan. Cover with plastic wrap and let rise in a warm place until doubled in size, about 1 hour. Bake until the top is lightly golden brown and a toothpick inserted comes out clean, about 30 minutes. Let rest for 5 minutes on a rack, turn out of the pan and cool on a rack for at least 30 minutes before slicing. Makes 1 loaf.
For the apple butter: Meanwhile, combine the cider, lemon juice, brown sugar, granulated sugar, cinnamon, clove, nutmeg and vanilla bean in a large Dutch oven over high heat and bring to a boil. Cook until the sugar has dissolved. Stir in the apples, bring to a boil, reduce the heat to low and cook, uncovered, stirring every 5 minutes or so, until the apples break down and the mixture thickens and becomes a deep brown color, about 45 minutes. Remove the vanilla bean.
Use an immersion blender to blend the mixture until it is very smooth and continue cooking another 15 minutes or so to thicken further. Transfer to a bowl and let cool to room temperature. Apple butter will keep, refrigerated in a container with a tight-fitting lid, for 1 week. Makes about 3 cups.
For the salted caramel whipped cream: Heat 1/4 cup cream in a small saucepan; keep warm. Combine the sugar and 1/4 cup water in a small saucepan and cook over high heat without stirring until it becomes a deep amber color, about 7 minutes. Remove from the heat, whisk in the warm cream, the butter and fleur de sel and let cool to room temperature.
Put the cream cheese in the bowl of a stand mixer and beat with the whip attachment until smooth. Add 1 cup very cold cream and the vanilla extract and whip until the mixture begins to thicken slightly. Add the caramel mixture and continue whipping until soft peaks form. Refrigerate until ready to use. Makes about 2 cups.
For the French toast: Slice the Sally Lunn bread into twelve 1/2-inch-thick slices. If the bread is fresh or not stale enough, preheat the oven to 300 degrees F. Put the bread on a rack set on a baking sheet. Let stale in the oven for 10 minutes. The bread should not get color, it should just dry out a bit. Remove and let cool.
Put a rack on a baking sheet. Whisk together the eggs and yolks in a large baking dish. Add the milk, cream, sugar, vanilla, orange zest and salt and whisk until smooth.
Melt about 3 tablespoons of butter in a large nonstick skillet over medium heat until the bubbles almost subside. Dip 4 slices of the bread in the custard mixture for about 1 minute on each side, making sure the bread is completely soaked through. Carefully remove the slices with a rubber spatula, shaking off excess custard, and cook until golden brown and cooked through, 2 to 3 minutes per side. Transfer to the baking rack and keep warm in the oven while you repeat with the remaining butter and bread.
Put 1 piece of French toast on a plate, top with a dollop of apple butter; add another piece of toast and more apple butter. Top with 1 more slice of French toast and a big dollop of salted caramel whipped cream. Sprinkle with fleur de sel and dust with confectioners' sugar. Repeat to make 3 more stacks and serve hot.