Place roast in a large stockpot and add cold water to cover. Cut onion in half and add to pot. Heat to boiling over high heat. Reduce heat; cover and simmer for about 1 hour 30 minutes. Remove beef from broth and let rest for 10 minutes; reserve broth. Shred beef, discarding excess fat. In large skillet, heat olive oil over medium heat. Add carrots and celery; cook for 5 minutes. Stir in shredded beef and raisins along with 1 cup of reserved broth. Heat and simmer over low heat for 5 minutes. Season with salt and pepper. Set aside and cool completely.
Measure masa harina, baking powder, coriander and salt into mixing bowl; mix well. Beat in pumpkin and shortening. Slowly, add warm broth, stirring in 1/2 cup at a time until moist enough to form a ball that is wet but not too sticky. Cover with wet towel and set aside.
When corn husks are soft and pliable, separate into individual pieces. Arrange 2 husks, slightly overlapping side by side, and alternating tips and stem ends to form rectangles about 9 x 7 inches. Spoon about 1/3 cup dough onto center of each corn husk; with wet fingers, spread to about 1/4-inch thick. Add about 1/4 cup shredded beef filling down center of dough. Fold long edges of husks over filling, lightly overlapping the edges. Fold ends under or twist and tie each end tightly with a narrow strip of corn husk to form a packet.
Arrange the tamales in a large steamer with seam side facing up. Add water to bottom part of steamer and heat to boiling. Steam tamales for about 2 hours or until they are firm to the touch.
Arrange tamales on a platter and serve while still very hot.
- 2 Pounds boneless beef chuck or shoulder
- 1 onion, peeled
- 1/4 Cup olive oil
- 1 Cup finely chopped carrots
- 1 Cup finely chopped celery
- 1 Cup California raisins
- Salt and pepper
- 3 Cups masa harina
- 1 Teaspoon gluten-free baking powder
- 2 Teaspoons toasted ground coriander
- 1 Tablespoon salt
- 1 Cup canned pumpkin (not pumpkin pie filling)
- 1/2 Cup whipped vegetable shortening
- 3 Cups chicken or vegetable broth, warmed
- 16 dried corn husks, soaked in warm water