- 8 ounces penne rigate (2 1/2 cups)
- 5 cups small cauliflower florets
- 2 tablespoons (1/4 stick) butter
- 1 1/2 tablespoons Dijon mustard
- 1 1/2 cups fresh whole wheat breadcrumbs made from crustless country-style bread
- 3/4 cup (packed) freshly grated Parmesan cheese plus additional (for serving)
- 1/2 cup heavy whipping cream
- 2 teaspoons finely grated lemon peel
- Cook pasta in large pot of boiling salted water 5 minutes, stirring occasionally. Add cauliflower. Cook until cauliflower is tender and pasta is tender but firm to bite, stirring occasionally, about 6 minutes. Drain pasta and cauliflower, reserving 1/2 cup cooking liquid. Return pasta and cauliflower to pot.
- Meanwhile, melt 2 tablespoons butter in large nonstick skillet over medium-high heat. Whisk in Dijon mustard. Add breadcrumbs. Cook until breadcrumbs are golden and crisp, stirring to break up clumps, 7 to 8 minutes. Transfer breadcrumbs to medium bowl.
- Add 3/4 cup grated Parmesan, cream, lemon peel, and 1/2 cup cooking liquid to pasta mixture in pot. Toss over medium heat until sauce simmers and coats pasta, 2 to 3 minutes. Season with salt and pepper.
- Transfer pasta to wide shallow bowl. Sprinkle with breadcrumbs. Serve, passing additional Parmesan cheese alongside.