Place the softened unsalted butter in a medium mixing bowl. Using a hand mixer or a stand mixer fitted with the paddle attachment, beat on medium speed for 1–2 minutes, until the butter is lighter in color and creamy around the edges of the bowl.
1/2 cup unsalted butter
Add 1 cup of powdered sugar to the creamed butter. Start mixing on low speed to avoid a sugar cloud, then increase to medium and beat until fully combined and smooth. Scrape down the sides of the bowl.
2 1/2–3 cups powdered sugar
Add another 1 to 1 1/2 cups of powdered sugar. Again, start on low speed and move up to medium, beating until incorporated. The mixture may look thick or slightly crumbly at this stage; that’s fine.
2 1/2–3 cups powdered sugar
Pour in the vanilla extract and add the fine sea salt, if using. Add 2 tablespoons of milk. Mix on low, then increase to medium, until the frosting is smooth and starting to look like a classic powdered sugar frosting—thicker than a glaze but easily spreadable.
3–5 tablespoons milk, 1 1/2 teaspoons pure vanilla extract, 1/8 teaspoon fine sea salt
Add more milk 1 tablespoon at a time, beating well after each addition, until the frosting reaches your desired consistency. For a thicker, spreadable frosting similar to a light buttercream, use about 3 tablespoons total. For a thinner, pourable glaze, use closer to 5 tablespoons. If the frosting becomes too thin, beat in 1–2 tablespoons more powdered sugar.
2 1/2–3 cups powdered sugar, 3–5 tablespoons milk
If desired, beat in ground cinnamon, maple syrup, cream cheese‑style spread, or heavy cream until fully incorporated. Taste and adjust with a little extra vanilla for more flavor or a tiny pinch of salt to balance sweetness.
1/2 teaspoon ground cinnamon, 1–2 tablespoons maple syrup, 1–2 tablespoons cream cheese‑style dairy‑free spread, 1–2 tablespoons heavy cream, 1 1/2 teaspoons pure vanilla extract, 1/8 teaspoon fine sea salt
Once the texture is where you like it, beat the frosting on medium‑high speed for 1–2 minutes to whip in a bit of air. This creates a light, fluffy frosting that spreads easily and gently melts over warm cinnamon rolls.
Let freshly baked cinnamon rolls cool for 5–10 minutes so they are warm but not piping hot. Spread or drizzle the frosting over the tops. It should soften slightly and sink into the swirls while still holding some shape.