Preheat your oven to 350°F (175°C) and line your baking sheets with parchment paper.

In a large mixing bowl, combine softened unsalted butter and brown sugar, and beat on medium speed for about 3-4 minutes until fluffy and light in color.

Add vanilla extract, ground cinnamon, and salt to the mixture and mix on low speed until just combined.

Gradually add all-purpose flour while mixing on low speed until a soft dough forms, about 1-2 minutes.

Lightly flour a surface and roll the dough to a thickness of about ¼ inch.

Cut the rolled dough into rectangles measuring approximately 3x4 inches and place them on the lined baking sheets.

Place a small dollop of filling in the center of half the rectangles, being careful not to overfill.

Cover each filled rectangle with the remaining unfilled rectangles, pressing edges together firmly to seal.

Bake for approximately 18 minutes until golden brown around the edges.

Allow cookies to cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.