Set your Big Green Egg to 350°F setup for direct grilling.
Mix the granulated garlic, oregano, basil, lemon pepper, salt, and onion powder thoroughly in a small bowl until the blend is uniform.
Apply a thin coat of olive oil to the chicken thighs and then dust both sides generously with your custom lemon garlic rub.
Grill the chicken skin side down for 4 minutes then flip cooking another 4 minutes
Set chicken aside and preheat cast iron pan in the Big Green Egg at 350°F
Add 1 Tbs olive oil and then the onions, stir for 1 minute
Add the minced garlic and cook another minute or two until fragrant
Add the chicken stock, lemon juice, and heavy cream stir
Add spinach and cannellini beans then stir
Add back in the chicken and any juices that accumulated and let the sauce reduce 10 minutes
Serve and enjoy