1. Preheat oven to 325°.
2. Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, oats, and next 4 ingredients (through salt) in a large bowl, stirring to combine. Add 1/4 cup warm water, oil, buttery sticks, and egg; stir with a fork until dough forms.
3. Cover a large baking sheet with parchment paper. Place dough in center of paper; gently press dough into a square. Cover dough with an additional sheet of parchment paper. Roll dough, still covered, into a 12 x 10-inch rectangle. Remove top sheet of paper; cut dough into 42 (1-inch) squares. Separate squares on pan.
4. Bake at 325° for 40 minutes or until crackers are golden brown and crispy. Remove crackers from pan; cool 20 minutes on a wire rack. Store in an airtight container up to 2 weeks.