In a large bowl, cream together the peanut butter, butter, brown sugar, and granulated sugar until light and fluffy.
Add the eggs, vanilla, salt, and baking soda. Mix until well combined.
Gradually mix in the flour just until incorporated.
Scoop the dough using a 3-tablespoon cookie scoop.
Roll each dough ball in granulated sugar.
Flatten slightly with the palm of your hand, then create the classic crisscross pattern using a fork.
Sprinkle with flaky sea salt, if desired.
Chill the cookies for 30 minutes.
Bake at 375°F for 10 minutes.
Immediately after baking, use a biscuit cutter or large round cutter to gently swirl around each cookie to create perfectly round edges. Allow the cookies to cool completely.
Melt the melting chocolate according to the package directions.
Pipe a swirl of chocolate onto the bottom of each cookie or pipe circles of chocolate directly onto parchment paper and gently press each cookie into the chocolate.
Allow the chocolate to set.
Melt additional chocolate and transfer it to a small decorating bag.
Snip a tiny opening in the tip and drizzle thin lines across half of each cookie.
Let the chocolate harden before serving or packaging.
