Cook the pasta according to the package directions. Reserve 3/4 cup of the cooking water; drain the pasta and return it to the pot.
In a large skillet over medium heat, cook the bacon until crisp, 6 to 8 minutes. Transfer bacon to a paper towel-lined plate. Let cool; then break into pieces.
Add the sage to the bacon drippings in the skillet and cook over medium heat, turning once, until crisp, 1 to 2 minutes. Transfer to the paper towel-lined plate.
Add the cauliflower, 1/4 cup water, salt and pepper to the skillet and cook, covered, for 2 minutes. Uncover and cook, tossing frequently, until golden and tender, 3 to 4 minutes more.
Add the reserved cooking water and 1/2 cup of the cheese to the pasta and toss until creamy. Add the cauliflower, sage, and bacon, and toss to combine. Sprinkle with the remaining 1/4 cup of cheese before serving.
NOTE: If you're pinched for time, you may use a jar of real bacon bits and 2 (10 oz.) packages of frozen cauliflower, thawed. One to two tablespoons dried sage may be substituted for 1/3 cup fresh sage.