Meanwhile, cook bacon in a large skillet over medium-high heat 5 to 6 minutes or until crisp; drain on paper towels, reserving drippings in skillet.
Sauté onion in hot drippings 4 to 5 minutes or until golden brown and tender. Add garlic; sauté 1 minute. Add collards; sauté 5 minutes. Remove from heat. Add bacon.
Whisk together eggs, egg yolk, next 3 ingredients, and 2 1/2 cups cheese in a large bowl. Drain pasta, reserving 1/2 cup pasta water, and immediately pour hot pasta into egg mixture; toss to coat. (The heat from the pasta will partially cook the eggs.) Add collard mixture; toss to combine. Stir in enough pasta water to reach desired consistency. Sprinkle with remaining 1/2 cup cheese.