On a Sheet Pan, roll puff pastry into a 10.5” square. Gently flip onto an appy maker. Using a rolling pin, firmly roll over to cut pastry.
Spoon Pesto Sauce onto each triangle: 1⁄2 tsp for small, 1–2 tsp for large and sprinkle entire surface with cheese. Starting at wide end, roll up each appy on the maker.
Place on a Sheet Pan lined with a Sheet Pan Liner. Using a basting brush, brush with milk, and bake until puffy and light golden: 10–11 minutes for small, 12–14 minutes for large.