In a medium mixing bowl, whisk together the flour, baking soda, and salt. Set aside.
1⅝ cups flour (1½ cups plus 2 tbsp), ¾ tsp baking soda, ½ tsp salt
Place the melted butter, peanut butter, white granulated sugar, light brown sugar, egg, egg yolk, molasses, milk, and vanilla extract in a large mixing bowl. Beat on low/medium speed using a hand mixer until all ingredients are well combined with no lumps.
½ cup salted butter, ⅔ cup creamy peanut butter, ¼ cup white granulated sugar, ½ cup light brown sugar, 1 egg, 1 egg yolk, 1 tsp molasses, 1 tbsp milk, 1 tsp vanilla extract (shop my favorite on Amazon)
Add the dry ingredient mixture to the wet ingredients and beat on low speed until just combined.
Use a spatula spoon to scrape the sides of the bowl and form the dough into a ball. Cover and refrigerate the dough for 1 hour. (See Note 2 below)
After the dough has chilled, preheat your oven to 350°F.
Using a #40 cookie scoop (1.5 tbsp), scoop the dough into your palm. Gently roll the dough between your hands to form a ball. Roll the dough ball in white granulated sugar, ensuring all sides are covered with a light layer of sugar. Place the cookies on a half sheet covered with a silicone baking mat (or parchment paper). There's no need to press these cookies down. They will spread on their own. The fully baked cookies are about 2.5" wide. I bake 12 cookies at a time on a half sheet pan. ⅓ cup white granulated sugar
Bake the cookies for 11 minutes at 350°F. There should be fine cracks forming on the top of the cookies and the bottom edges should barely be starting to turn golden when the cookies are done.
Leave the cookies on the pan to cool for 5 minutes before gently pressing a Hershey's Kiss into the center of each cookie. Do not press too hard- it will crack the cookies!
24 Hershey's Kisses
Transfer the cookies to a wire cooling rack to finish cooling. The chocolate will take at least 40 minutes to an hour to firm back up, but feel free to taste test one (or two or three) before then! Store the cookies in an airtight container once completely cooled.