In a small bowl, combine warm milk and sugar, then sprinkle the active dry yeast on top. Let bloom for 5-10 minutes until frothy.

In a large bowl, mix all-purpose flour, salt, and sugar for the dough. Add the yeast mixture, beaten eggs, unsalted butter, and vanilla. Mix until a slightly sticky dough forms.

Place the dough in a greased bowl, turning to coat lightly in oil. Cover with a towel and let rise in a warm area for 1.5 to 2 hours, until doubled in size.

Combine softened butter, brown sugar, cinnamon, nutmeg, and salt in a bowl. Blend until well combined.

In a saucepan, combine unsalted butter, brown sugar, maple syrup, and heavy cream over medium heat. Stir until thick and bubbly, then remove from heat.

Roll out the risen dough into a rectangle measuring about 12x18 inches. Spread the filling evenly over the dough using a spatula.

Starting from the long edge, tightly roll the dough into a log. Cut into 1.5-inch pieces with a knife or dental floss.

Arrange the cut pieces in a greased baking dish with space to rise.

Pour the topping over the sliced buns and cover with a towel. Let rise for another hour.

Preheat the oven to 350°F (175°C) and bake for 40-45 minutes until golden brown and bubbly. Let cool slightly before flipping onto a serving tray.