Heat oil in a sauté pan over medium heat. Add onion and cook for 1 minute. Add garlic, curry powder, ginger, cumin, salt, red pepper flakes, coriander, cayenne pepper, celery seed, tarragon, and cinnamon. Cook until fragrant, about 1 to 2 minutes more. Add potatoes and mixed vegetables and cook, stirring constantly, for 3 minutes.

Pour broth into the potato mixture. Reduce heat to medium-low and cook, stirring occasionally, until potatoes are tender and broth is mostly absorbed, about 12 to 15 minutes.

Place flour in a medium bowl. Make a well in the center, then add salt, oil, and water. Mix until it forms a stiff dough, roll it into a ball, and cover with plastic wrap. Let rest for 30 minutes.

Divide dough into 8 balls. Roll each ball into a 10-inch circle and cut into halves. Moisten edges, shape each half into a cone, and fill each cone with 1-2 tablespoons of filling. Pinch edges to seal.