Preheat the oven to 375°F (190°C).
Prepare a baking sheet by lining it with parchment paper.
Unroll the crescent roll dough and separate it into triangles.
Spread a thin layer of Dijon mustard on each triangle.
Sprinkle shredded cheddar cheese over the mustard on each triangle.
Place a sausage link at the wide end of each triangle and roll it up.
Place the rolled pigs in a blanket on the prepared baking sheet.
Brush the tops with the beaten egg and sprinkle with poppy seeds.
Bake in the preheated oven for 12-15 minutes or until golden brown.
Remove from the oven and let cool slightly before serving.