In a deep skillet with a cover, add 3 tablespoons of olive oil and 1 sliced celery stalk. Heat over medium-high heat until the celery slice is sizzling, about 3 to 5 minutes.
Add the remaining sliced celery, 1 quartered onion, and 1 chopped garlic clove to the skillet. Turn the heat to medium and cook, stirring occasionally, until slightly tender, about 5 minutes.
Mix in 1 cut head of cauliflower, 1 can of peeled, drained, and mashed tomatoes, 1 teaspoon of sage, and salt and ground black pepper to taste. Cook and stir over medium-high heat until bubbling, about 5 minutes.
Cover the skillet with a lid, reduce heat to low, and cook until a knife slides easily into the cauliflower, about 15 minutes. Add 2 tablespoons of chicken broth if the tomato and cauliflower sauce begins to burn.
In a large pot, bring lightly salted water to a boil. Cook 1 package of linguine pasta at a boil until tender yet firm to the bite, about 11 minutes. Drain and transfer to a serving bowl.
Pour the tomato and cauliflower sauce over the pasta and add 1 cup of grated Parmesan cheese. Toss to coat.