Step 1

For the filling: Heat 1 tablespoon of the oil in a large skillet over medium heat. Add the onions and cook until slightly softened, 2 to 3 minutes. Place the sweet potatoes in a medium bowl and toss them with the remaining 1 tablespoon oil and a pinch of salt. Push the onions to the side and add the sweet potatoes to the skillet. Cook, stirring occasionally, until the potatoes begin to soften and the onions caramelize, about 5 minutes.

Step 2

Add the garlic, habanero, thyme, ginger, smoked paprika and allspice; cook, stirring, for 1 minute. Add the lentils and toss until combined. If the mixture becomes dry, stir in 1 to 2 tablespoons of water to loosen any dry bits, then season to taste with salt and pepper. Remove from the heat and set aside to cool slightly.

Step 3

For assembly: Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper.

Step 4

Mix the oil and curry powder in a small bowl.

Step 5

Unroll the phyllo dough on the counter with the shorter end facing towards you. Cut the phyllo in half lengthwise with a sharp knife so the sheets are about 6 1/2-by-18 inches each. Stack the cut sheets on top of each other. Cover the stack with a moistened kitchen towel or paper towels to keep the phyllo from drying out.

Step 6

Set a half sheet of phyllo on the counter with the shorter end facing towards you and brush the sheet lightly with the curry oil. Fold the sheet in half from left to right so that you have one long narrow strip. Brush it again with the curry oil, then place 1 tablespoon of the filling on the bottom right corner of the phyllo. Fold the right corner up toward the left side of the sheet to form a triangle, then keep folding up in a triangle shape along the length of the phyllo, brushing each fold lightly with the curry oil; place the completed pie on the prepared baking sheet and brush the top lightly with curry oil. Continue with the remaining filling, phyllo and curry oil.

Step 7

Sprinkle all the pies lightly with kosher salt. Bake until golden and crisp, about 15 minutes. Let cool for 5 minutes before serving.

Step 8

Meanwhile, for the cool yogurt dipping sauce: Whisk together the yogurt, lemon zest and juice and mint in a small bowl. Season to taste with salt and pepper. Refrigerate until ready to use. Serve the hot pies with the dipping sauce.