Cream together peanut butter, butter, brown sugar, egg, and vanilla extract for three minutes.
In another bowl, whisk together flour, baking powder, cinnamon, ginger, nutmeg, cardamom, clove, allspice, black pepper, and sea salt.
Fold peanut butter mixture into flour mixture and stir by hand until just combined to form the cookie dough
Cover the dough and chill for at least one hour.
Preheat oven to 375 degrees Fahrenheit and line a cookie sheet with parchment paper.
Scoop dough into two-inch balls and place on prepared cookies sheet, leaving at least two inches space between each. Use a fork to press a criss-cross pattern into the top of each cookie.
Transfer pan to oven and bake for about 10 minutes or until cookies are golden brown and firm to touch.
Remove from oven and cool for three minutes then sprinkle each cookie with flaky sea salt.