Heat the milk in a saucepan over medium-low heat until just warm, around 105-110 degrees F. Stir in 1 tablespoon of the sugar. Sprinkle the yeast overtop and let sit until foamy, about 5 minutes. Once foamy, whisk in the eggs until smooth.
Place the flour and salt in the bowl of your electric stand mixer (I used the paddle attachment). Slowly add the milk mixture and mix on low speed until combined. Add the butter 1 piece at a time, beating until combined. Mix on medium-high speed for 5 minutes to knead the dough, it should be silky and smooth. Remove the dough and place it in an oiled bowl, then cover with plastic wrap. Let sit and double in size for 1 to 2 hours.
Right before the dough is ready, make the nutella caramel. Add the butter to a saucepan over medium heat. Once melted, stir in the sugar, cream, honey and salt. Bring to a boil then reduce to a simmer and cook for 3 to 4 minutes until glossy and smooth. Remove from heat and stir in the vanilla extract. Stir in the nutella. Pour almost all of the mixture, reserving about 1/2 cup, in an 9×13 baking dish. Sprinkle the almonds on top. (Note, I LOVE the honey toasted almonds from Trader Joe’s so I use those, but you can add dry sliced almonds to a skillet over medium-low heat and toss for 3 to 4 minutes until toasted.) At this point you can also drop some spoonfuls of nutella right on top of the mixture – I totally did that.
Take the dough and roll it out on a floured surface into a large rectangle, about 18x 12 inches or so. Brush the melted butter all over the dough. Spread the nutella all over the dough, leaving a 1-inch boarder around the outsides. Combine the sugar, cinnamon and salt and sprinkle it overtop. Tightly roll the dough up from one of the long ends into a long log. Slice into 1-inch (about) rounds. Place the rounds on top of the almonds and caramel in the dish. Brush with melted butter and cover with plastic wrap. Let rise in a warm place for 30 to 45 minutes.
Preheat the oven to 350 degrees F. Bake the buns, uncovered, for about 45 to 50 minutes, covering with foil if they start to brown too much. You want the bottom to be bubbling and the buns to be set. Remove from the oven and cover with the remaining nutella caramel. Let sit for 15 to 20 minutes, then carefully invert the pan so the buns flip out and the caramel and almonds are on top. Serve immediately.