Cook sausage in large cast-iron or oven- proof skillet over medium-high heat 8-minutes or until thoroughly cooked, stirring frequently; drain. Set aside.
Combine cream cheese, mayonnaise, 1 cup shredded cheddar cheese, Monterey Jack cheese, jalapeños and garlic in a large bowl; mixing until well blended. Stir in cooked sausage; mix lightly.
Cut each biscuit in half and roll into a ball. Place biscuits around the edge of a cast-iron or oven-proof skillet, forming a ring. Brush biscuits with beaten egg combined with water and sprinkle with salt.
Spoon dip in the center of the bread ring in the skillet. Sprinkle with remaining ½ cup cheddar cheese. Bake for 25-minutes or until biscuits are golden brown and dip is hot and bubbly. Sprinkle with green onions, before serving.