Preheat to 375°F (190°C). Line a baking sheet with parchment or a silicone mat.
Mix chopped pecans, brown sugar, corn syrup, melted butter, vanilla, cinnamon (optional), and a pinch of salt in a bowl.
Unroll crescent dough and separate into 8 triangles.
Spoon 1–1.5 tsp of filling onto the wide end of each triangle.
Roll up each triangle from the wide end, sealing edges gently.
Mix 1 beaten egg with 1 tbsp water. Brush over crescents.
Bake for 10–12 minutes until golden and puffed.
Let cool 5–10 minutes. Best served warm.