How to Make It
Let pizza dough stand at room temperature 15 minutes. Preheat oven to 450°F.
Heat a large skillet over medium-low. Add oil and garlic; cook, swirling occasionally, until garlic is golden, about 2 to 4 minutes. Drain oil from skillet into a small bowl to reserve, keeping garlic in skillet. Add spinach to skillet; increase heat to medium-high, and cook, tossing constantly, until spinach is wilted, about 2 minutes. Let stand 10 minutes to cool.
Stir together ricotta and Parmesan in a medium bowl. Add spinach mixture and chicken; stir well to combine.
Place dough on a large piece of parchment paper, and roll dough into a 20- x 6-inch rectangle. Spoon chicken mixture down center of dough to make an approximately 20- x 3-inch strip. Using a pizza cutter or sharp knife, create tabs in dough on both sides of filling: Starting at the edge of dough, cut 1 1/2-inch-long diagonal slits (1/2 inch to 3/4 inch apart) in toward filling. Fold tabs over filling, and pinch tabs together to seal. Carefully shape stuffed dough into a ring; pinch ends of dough together to seal.
Transfer stromboli ring on parchment to a baking sheet; fold or cut away excess parchment to fit baking sheet. Brush half of reserved garlic-infused oil over dough. Bake stromboli at 450°F until dough is browned, about 18 minutes. Remove from oven; brush with remaining garlic oil. Let stand 5 minutes before serving.
Stromboli Ring Step-By-Step
1. Spoon filling down the center of the dough; create tabs by cutting diagonal slits about 1/2 to 3/4 inch apart on either side.
2. Fold dough tabs over filling. Pinch tabs together over center of filling to seal and hold dough in place as it bakes.
3. Carefully and slowly bring the ends of the dough together to form a circle.
4. Once dough comes together into a circle, pinch the ends together to seal the ring and hide the seam.