Preheat the oven to 450 degrees F. Line a baking sheet with parchment paper.
Pulse the flour, thyme, pepper, baking powder, salt and sugar in a food processor until thoroughly mixed. Add the melted butter and pulse 5 to 6 times.
Add the water and pulse just until the dough starts to stick together (about 10 seconds). Remove the dough, press together gently with your hands to form a single square mass, and cut into four squares. Let the dough rest for about 10 minutes at room temperature.
Roll out each individual piece of dough on a lightly-floured surface into a rectangle as thin as you can possibly get it. If the dough starts to shrink up, let it rest a little longer. Cut the rectangle in half lengthwise. Cut each half into 2-inch-wide pieces. Place the pieces on the baking sheet.
Bake, checking periodically to make sure the crackers aren't getting too brown, for 4 to 5 minutes, then flip each cracker piece and bake another 4 to 5 minutes. Let cool on the baking sheet to get crispy.