Preheat the oven to 200°C (400°F)

The filling

1. Add 15 mL (1 tbsp) of butter to a skillet over high heat and sear the lamb in two batches so it browns well, about 3 minutes. Let cool, then add the lemon zest, thyme, nutmeg, raisins, remaining butter, salt and pepper.

Pastry dough

1. With a 4 cm (1.75 inch) cookie cutter, cut 40 rounds of dough for the tops and bottoms of the tartlets.
2. Cut 20 strips of dough, roughly 5 cm x 12 cm (2 inch x 4.7 inch), as well.

Assembly

1. In a small bowl, beat the egg with a bit of water.
2. Brush the edges of 20 dough rounds with the egg mixture and place, moist-side up, on a baking sheet lined with parchment paper.
3. Shape 20 cylinders with the dough strips by overlapping the ends and sealing them together with the egg mixture.
4. Line up each cylinder along the moist edges of the dough rounds to make a little top hat and seal into place.
5. Fill with the lamb mixture.
6. Moisten the edges of the remaining 20 rounds and place on top of each cylinder, like a cover, and seal by pinching the edges together all the way around.
7. Once all the petits pâtés are assembled, brush with the remaining egg mixture and sprinkle with sugar.
8. Refrigerate for 30 minutes.
9. Bake for 40 minutes. Serve hot or at room temperature.