Preheat 335°F. Line 3 pans.
Whisk wet ingredients.
Add dry ingredients.
Mix just until combined.
Divide evenly between pans.
Bake 22-25 min.
Cool completely.
Melt butter.
Stir in sugar + cinnamon.
Stream in cream.
Simmer 1-2 min.
Add salt + vanilla.
Cool completely.
Whisk in milk as needed.
Beat butter.
Add cream cheese.
Add powdered sugar.
Add vanilla + salt.
Mix until smooth.
Add milk if needed.
Chill briefly if needed.
Thin frosting layer + dam.
Add cinnamon filling.
Repeat.
Add top layer.
Chill briefly.
Frost exterior.
Drizzle or swirl remaining filling on top.
