Grilled Flatbreads with Caramelized Onions, Sausage, and Manchego Cheese

Ingredients

• 2 tablespoons balsamic vinegar 
• 0.5 cup wine dry red (such as Zinfandel)
• 0.8 pound ground sausage sweet italian ( 4 links)
• 2 cups manchego cheese shredded divided packed ()
• 1.5 pounds onion red halved thinly sliced
• 1 teaspoon sugar 
• 2 tablespoons vegetable oil 

Equipment

• bowl
• frying pan
• baking sheet
• pot
• grill

Directions

1. Heat vegetable oil in heavy large pot overmedium-high heat.
2. Add onions and sautéuntil soft and deep golden brown, stirringoften, about 10 minutes. Stir in wine, vinegar,and sugar. Reduce heat to low and simmeruntil almost all liquid is absorbed, stirringoften, 3 to 4 minutes. Season to taste withsalt and pepper.
3. Transfer to small bowl. Cool.
4. Heat medium skillet over medium heat.
5. Add sausage; sauté until cooked throughand browned, breaking up with back of fork,5 to 6 minutes.
6. Transfer to small bowl. Cool.DO AHEAD: Onions and sausage can be made1 day ahead. Cover separately; chill. Bring toroom temperature before using.
7. Prepare barbecue (medium-high heat).Lightly flour 2 rimless baking sheets. Dividepurchased pizza dough in half (if using).Working with 1 dough round or dough halfat a time, roll out on lightly floured surfaceto 12x8-inch oval.
8. Transfer to baking sheets.Spray top of flatbreads with nonstick spray.
9. Invert flatbreads, sprayed side down,onto grill. Cook until grill marks appearand sides of bread are dry, 3 to 5 minutes.Return to same baking sheets, grilled sidedown. Spray uncooked side with nonstickspray. Turn flatbreads over on baking sheets,grilled side up.
10. Sprinkle 3/4 cup cheeseover each flatbread.
11. Sprinkle onions, thensausage, over flatbreads, dividing equally.
12. Sprinkle remaining 1/2 cup cheese over,dividing equally. DO AHEAD: Can be made 2hours ahead.
13. Let stand at room temperature.
14. Transfer flatbreads, topping side up, togrill. Cover and cook until crusts are crispand cheese melts, 3 to 5 minutes.
15. Transfer towork surface.
16. Cut into rectangles and serve.
17. * A Spanish cheese made from sheep’s milk;sold at some supermarkets and at specialtyfoods stores.