How to Make It
Place flour, salt, and sugar in the bowl of a food processor; pulse until well combined, 3 to 4 times. Add butter to processor bowl; pulse until mixture looks sandy, 7 to 8 times, making sure all butter is incorporated. Whisk together half-and-half and egg in a small bowl; add to processor bowl. Pulse until mixture forms a ball, 6 to 7 times.
Place dough on a lightly floured surface; knead until smooth, 4 to 5 times. Divide dough in half; shape each half into a disk. Cover with plastic wrap, and chill about 1 hour.
Preheat oven to 425°F. Working with 1 dough disk at a time, roll dough to 1/8-inch thickness on lightly floured surface. Cut dough into desired shapes, and place 1 inch apart on parchment paper-lined baking sheets. Bake in preheated oven until edges are golden brown, 11 to 12 minutes, switching pans top rack to bottom rack after 6 minutes. Cool on pan about 5 minutes; remove crackers to a wire rack, and cool completely, about 10 minutes.