In a large bowl, combine the flour, baking soda and baking powder.

Using an electric mixer, beat the peanut butter, sugars, and shortening until creamy. Add in the eggs and vanilla extract and mix until combined. Stir in the English Toffee Bits.

Gradually add the flour mixture into the wet mixture, stirring until well-combined. Cover dough and refrigerate for 20 minutes.

While dough is chilling, preheat oven to 350°.

Remove dough from refrigerator and shape into 2" balls. Place dough balls on parchment-lined baking sheets, keeping them about 2" apart. Bake on center rack of the oven for approx. 15 minutes or until light golden brown.

If using regular size marshmallows, place one in the center of each cookie while cookie is still hot. Press down on the marshmallow to firmly stick it to the cookie. If using the giant marshmallows, cut the marshmallow in half horizontally before placing it on the cookie.

Place the cookies under the broiler to toast the marshmallows, being cautious not to let them burn. After removing the cookies from the broiler, press a chocolate kiss into the center of each marshmallow. Remove cookies to baking racks to cool.