Spray the slow cooker dish with nonstick cooking spray and set aside.
Wash and chop onions, mince garlic cloves and cut asparagus into 1-inch pieces. Set asparagus aside.
Using a zester or microplane grater, zest the lemon and then squeeze the juice into a cup and set aside.
In a large (12 inch) skillet, heat the olive oil over medium-high heat. Add the onion and cook until softened, about 3 to 5 minutes. Then, stir in the garlic.
To the skillet, add the rice and cook for 3 minutes, stirring often to avoid burning.
Add the wine into the skillet and stir, cooking until almost completely absorbed into the rice.
Pour the rice mixture into the slow cooker and slowly stir in the heated broth, lemon juice, lemon zest, salt, and black pepper.
Cover the slow cooker and cook on high for 90 minutes.
After 90 minutes, remove the lid and stir in the fresh asparagus. Continue cooking for an additional 30 minutes.
Once asparagus has reached your desired consistency, stir in the butter and Parmesan cheese.
Serve and enjoy!
Notes
Leftovers can be stored and refrigerated in an airtight container.