Heat the griddle to about 400-425 degrees F.
Add about 1-2 tablespoons of your favorite cooking oil to the heated surface, and spread it out in a thin even layer with your spatula.
Place the whole tomatillos, quartered onion, and jalapeños on the oiled surface. Allow to cook and "blister" on the first side before rotating.
When you notice a nice char, begin to rotate the ingredients to soften the skins of the fruits and vegetables and to develop a nice char on the other sides. *This is as easy as rolling the tomatillos and jalapeños across the hot surface every few minutes or so. If needed you can use a melting dome and a squirt of water to create steam and to speed up the cooking process.
When the tomatillos and other ingredients are about 75% done, add the whole peeled garlic cloves to the griddle to toast.
As the tomatillos, jalapeños, garlic, and onion are done charring on the griddle, transfer to a large blender cup. *The tomatillos will go from a bright and vibrant neon green to a muted yellow-green color.
Add cilantro, juice of 1 lime, and a pinch of salt to the grilled ingredients in the blender. Cover the blender cup and pulse for a few seconds, or until the tomatillo salsa is blended to your desired consistency. Taste for seasoning, and add more salt, cilantro, or lime juice if you wish.
Pour into a bowl and serve.