In a food processor, fitted with the blade attachment, add the dry ingredients and pulse 3 times for 2 seconds each. Add in the half-and-half and the butter and pulse for 10 second intervals, 4 to 5 times, or until a dough starts to form. If the dough seems crumbly, and not binding, drizzle in a few drops of the water, a little at a time, until it binds.
Turn out onto a lightly floured board and knead a few times. Divide in half, cover with plastic wrap and let rest at room temperature for 10 minutes.
Preheat the oven to 375 degrees F.
Put a silicone baking mat on your work surface and roll the dough into a rectangle, about 6 by 9 inches and 1/4-inch thick. Evenly trim the edges, adding back any trimmings to the second portion of dough. Cut 2-inch strips with a knife, but leaving the dough in place. Then cut diagonals to form triangular pieces, 2 inches on their long side. Repeat, gently transferring them to a baking sheet fitted with a silicone baking mat, spacing them 1-inch apart. Repeat with second half of dough.
Bake for 9 to 12 minutes, checking carefully after 9 minutes. Crackers will start to turn golden.
Remove from oven and let cool. Store tightly covered for up to 3 days.