Cream together the butter and sugar in a stand mixer fitted with the paddle attachment on medium speed until combined and fluffy. Note: If you don't have a stand mixer, use a large bowl and an electric mixer.

Scrape the sides of the bowl with a rubber spatula and add the peanut butter. Beat on medium-high speed until well combined. Scrape the sides of the bowl again.

Add the egg and vanilla extract and beat until all of the wet ingredients are well-combined. Scrape the sides of the bowl.

In a separate bowl, combine the remaining dry ingredients (gluten free flour, baking soda and sea salt).

Pour the dry ingredients into the stand mixer with the wet ingredients and beat until everything is well combined. The dough will be very soft and sticky. This is normal.

Cover the bowl with plastic wrap and refrigerate for 30 minutes.

Preheat the oven to 350 degrees Fahrenheit and line a 8” x 8” square pan with parchment paper (you can also spray it with cooking spray).

Spread the peanut butter cookie dough into the prepared pan in an even layer.

Bake on the center rack of the preheated oven for 20 to 30 minutes, or until the edges are turning slightly golden brown. For chewy bars, bake until the center has firmed up but doesn’t look entirely set up (about 30 minutes). For crispier bars, bake for 30 to 35 minutes.

While the bars are baking, peel 16 chocolate kisses.

Remove the bars from the oven and immediately arrange the chocolate kisses on top. I make 4 rows of four kisses, to create 16 bars. The kisses will begin to melt as soon as they touch the hot bars, which is what will ensure they stay put.

Allow the bars to cool completely before slicing. You can also transfer the bars to the freezer for 15 minutes to help them set up faster.

Transfer the bars to a cutting board by lifting up on the edges of the parchment paper. Use a sharp knife to cut the bars, ensuring the chocolate kisses stay in the center of each bar.

Serve and enjoy!