Mix the flour and salt. Add the warm water gradually and knead for 8 to 10 minutes until smooth and firm.
Cover the dough and rest it for 30 minutes at room temperature.
Mix and Shape:
Combine the beef, lamb, onion, garlic, salt, pepper, and caraway. Mix in the cold water until the filling is cohesive but not pasty.
Divide the dough into 24 pieces. Roll each into a 4-inch round with a slightly thicker center.
Place about 2 tablespoons of filling in each round. Gather and pinch the edge into uneven pleats, leaving a small opening at the top.
Steam:
Line a steamer with perforated parchment and arrange the buuz with room between them.
Steam over steadily simmering water for 18 to 20 minutes, until the dough is tender and the filling reaches 160°F (71°C). Rest for 2 minutes before lifting them out.
Notes
Keep the unused dough covered so the wrappers do not dry while shaping.
Freeze uncooked buuz on a tray, then bag them; steam from frozen for about 5 minutes longer.