In medium skillet, heat oil; sauté onions and garlic until onions are softened. Stir in spinach; cook 1 minute, stirring constantly, until just wilted. Remove from heat and stir in lemon juice and rind; chill well.
On lightly floured surface, roll half of puff pastry into a 10-inch (23 cm) square. Remove 2-inch (5 cm) strip from one side; reserve. Cut remaining square in half. Fold each piece in half to form a square; roll to a 6-inch (15 cm) square. Repeat with remaining pastry, creating 4 squares and 2 strips. Spread turkey with mustard and sprinkle with rosemary.
Place 1 piece of turkey on each pastry square. Top each with 1/4 of chilled spinach mixture. Join opposite corners of pastry together, sealing edges well. Slice each pastry strip into 4 length-wise pieces; twist 2 pieces together. Cut each twist in half crosswise. Place 1 twist over each sealed edge.
In small bowl, combine egg yolk and water. Brush over pastry. Bake in 425ºF (220ºC) oven for 30 to 35 minutes or until pastry is golden brown.
Bon Appetit! Take a photo and share this recipe #ThinkTurkey
Sign-up for our Canadian Turkey E-Newsletter
Get the latest tips and recipes delivered to your inbox