Preheat oven to 400 F.
Heat olive oil in a frying pan and sautee onions and garlic until slightly browned.
Let mixture cool (or pop in fridge), then add to a mixing bowl along with the ground pork, breadcrumbs, salt, pepper, and sage.
Mix with hands until just combined. Do not overmix.
Roll out one sheet of the puff pastry. Use a pizza cutter to cut in half.
Place 1/3 of the filling mixture vertically along the center of the half pastry sheet. You want a thick band of filling from top to bottom.
Lightly beat the eggs in a small bowl. Use a pastry brush to paint one end of the pastry sheet.
Carefully fold the pastry sheet over the filling, creating a seam in the middle.
Cut the roll in half to make two equal size rolls.
Flip the rolls over, seam side down, onto a non-stick baking sheet. Brush the top of the rolls with egg wash and make three horizontal cuts in the top of the roll.
Repeat process with other half of the puffed pastry. Cut second sheet of puff pastry in half and repeat with half. You will have one half sheet leftover.
Bake rolls for 20-25 minutes, until they are golden brown and baked through. Let cool slightly before eating.