Whisk together the flour, baking powder, and salt in a medium bowl, then set this dry mixture aside.

In a large bowl, use a mixer to beat the softened butter and granulated sugar until smooth and creamy for about two minutes. Incorporate the egg and vanilla extract, beating for one minute until combined, scraping the bowl as necessary.

Add the reserved dry ingredients to the wet mixture and mix on low speed until just combined; if the dough is too soft, mix in one more tablespoon of flour.

Divide the dough into two equal portions, rolling each into a 9x7-inch rectangle about 1/4-inch thick on a floured silicone mat or parchment paper. Spread one tablespoon of melted butter onto each rectangle, then evenly sprinkle a mixture of granulated sugar and cinnamon over both.

Slowly and tightly roll each rectangle into a 9-inch log, smoothing any cracks, then transfer the logs to a cutting board or plate and chill, loosely covered with plastic wrap, for at least 2 hours or up to 3 months in the freezer.

Preheat your oven to 350°F (177°C) and prepare a large baking sheet by lining it with parchment paper or a silicone baking mat.

Remove the chilled dough logs from the refrigerator and cut them into 1/2-inch thick slices, arranging the slices about 2 inches apart on the prepared baking sheets.

Bake for 10-11 minutes, or until the sides are lightly browned, then let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.

Whisk together all the vanilla glaze ingredients until smooth, then drizzle the prepared icing over the cooled cookies.

Store the covered cinnamon roll cookies at room temperature for up to 5 days.