Add the warm milk, yeast, and sugar to a large bowl. Set aside until the yeast has bloomed – about 5 minutes.
Next, add the egg, vanilla, and melted butter. Whisk to combine.
Using a stand mixer on low-medium speed with the dough hook attachment, slowly stir the flour and salt into the wet ingredients. Once all of the flour has been added and a shaggy dough has formed, knead for 2-3 minutes or until the dough is smooth and elastic (it should bounce back when you poke it).
Transfer the dough to a lightly oiled bowl and cover it with plastic wrap and then a tea towel. Place it in a warm place to rise until doubled in size – about 1-1.5 hours.
While the dough rises, make the filling. In a small bowl add the softened butter and sugar. Using a hand mixer mix until the butter and sugar are light and fluffy.
Then, add the almond extract, almond flour, and egg to the creamed butter and sugar and mix to combine. Refrigerate for 15 minutes.
Once the dough has risen, turn it out onto a lightly floured surface.
Roll it into a rectangle that is approximately 18” long, 12” wide, and ¼” thick.
Spread the filling over the dough and then roll it into a tight log, starting at one of the long sides.
Slice the log into 1” rolls. This will yield 9-12 rolls, depending on how tightly you roll your log and whether you start rolling at a long or short side of the dough.
Butter a 9x13 baking dish or line it with parchment paper. Add the rolls to the dish, making sure they just barely touch. Sprinkle the almond slices over the rolls.
If you’re making the rolls in advance, wrap them in plastic and place them in the fridge for up to 12 hours. Bring the rolls to room temperature (about 30 minutes) when you’re ready to bake and then skip to step 13.
If you aren’t making the rolls in advance, cover with plastic wrap and then a tea towel, and place them in a warm spot to rise until the rolls begin to touch - about 30 minutes. While the rolls rise, preheat your oven to 350℉.
Bake the cinnamon rolls for 20-25 minutes or until the centers are set and the top is golden brown.
While the cinnamon rolls are baking, make the vanilla glaze. Add all of the ingredients to a bowl and mix to combine. Set aside.
Allow the cinnamon rolls to cool for at least 10 minutes before icing.