Old-Fashioned Peanut Butter Cookies

Preheat the oven to 375°F (190°C). Line a baking sheet with parchment paper.
In the bowl of a stand mixer using the paddle attachment, beat the granulated and brown sugars and butter on high until light and fluffy, about 3 minutes. Add the peanut butter, eggs, and vanilla, reduce the speed to medium, and beat until thoroughly combined.
Mix the flour and salt together in a small bowl. With the mixer on low, slowly add the flour and salt to the peanut butter mixture and blend thoroughly. In a small bowl, stir together the baking soda and hot water and add it to the cookie dough, mixing until just combined.
Drop the dough in heaping tablespoons onto the parchment. Gently press a fork into each cookie, first vertically, then horizontally, to create the classic peanut butter cookie crisscross. (If an extra sparkly, extra crunchy cookie is desired, dip your fork in a little granulated sugar prior to pressing it into the dough.)
Bake for 8 to 12 minutes, until the cookies have barely begun to turn golden at the edges.
Let the cookies cool for a minute or more on the baking sheet, then move them to a wire rack to cool at least a little. (The cookies will get crisper the longer they cool.) Store the cookies in an airtight container for up to 5 days.