Separate out a slightly heaping ⅓ cup of the pecan pieces and mince them into small pieces with a sharp knife on a cutting board. Set the other pecan pieces aside for now.

In a medium-sized mixing bowl, whisk together the flour, minced pecan pieces, powdered sugar, and brown sugar until well combined.

Grate the frozen butter into the flour mixture and mix using a hand mixer.

Use a hand or stand mixer to beat in the milk (heavy cream or half and half) 1 tablespoon at a time, to the dough, just until the dough comes together without needing to be pressed.

Once the dough is formed, turn it out onto a large sheet of plastic wrap and press it into a long, even log.

Wrap the dough well with the plastic wrap, pressing it into a firm log, and then place the dough in the freezer for at least 10 minutes.

When ready to bake your cookies, preheat your oven to 350º F and line two baking sheets with silicone baking mats or parchment paper.

Remove your dough log from the freezer and use a sharp knife and cutting board to cut thick slices of the dough, at least ½ inch to 1 inch thick.

Place the cookies on the prepared baking sheets, about 1 inch apart.

Top the cookies with the remaining pecan halves or pieces and then bake for 12-15 minutes or until the edges are golden brown.

Remove from the oven and let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely before serving.