Place your American lamb shoulder on a baking sheet. Allow it to sit at room temperature for at least an hour.     

Preheat a large skillet to medium-high heat. Season your lamb shoulder with salt and pepper. Sear the lamb on both sides until slightly golden brown for about 5 minutes. Meanwhile, add the sliced yellow onion to the bottom of your slow cooker. 

Place the lamb shoulder on top of the onions. Next, deglaze the skillet with red wine and pour the drippings from the skillet over the lamb. Pour the chicken stock into the slow cooker. Cook the lamb on high for 4 hours or on low for 8 hours. To ensure the lamb shoulder is cooked you can check the internal temperature and it should be a minimum of 145 degrees Fahrenheit*. Also, let the lamb shoulder rest for a three-minute rest prior to shredding.

Note: The USDA recommends that lamb reach an internal temperature of at least 145 degrees F with a 3-minute rest

Meanwhile, prepare the relish. In a saucepan preheated to medium heat, melt the  butter. Add the sweet onion and granulated sugar. Stir to combine and continue to cook for about 10 to 15 minutes until nice and golden brown. 

Once cooked, remove the saucepan from the heat and add in the red bell pepper, cilantro, lime juice, salt, and pepper. Set aside. 

To serve, remove the lamb shoulder from the slow cooker and shred with a fork. Place some of the shredded lamb on a slider bun bottom. Top the lamb with relish and top with remaining bun. Repeat the process and enjoy!