Romanesco Broccoli: Fractals, Fibonacci and a Feast

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Currently available at the East Lansing Farmers Market, Romanesco broccoli seems to be a space alien among the squash and apples. Growing in bright green spirals that resemble sea creatures, minarets, or tiny pointed firs on an island, it is actually an edible flower in the Brassica branch of the mustard family. Brassicae include the more familiar cauliflower, broccoli and Brussels sprouts.

Although no one knows for sure, Romanesco broccoli appears to have been bred in 16^th century Italy between Rome and Naples, and defies classification – some scientists argue that it’s a cauliflower, some that it’s a broccoli, and still others that it’s a kind of cabbage. (For purposes of this article, we’re going with broccoli). Its popularity has grown in the United States as it’s become popular with organic farmers.

For cooking and eating Romanesco broccoli acts a lot like any old broccoli or cauliflower. According to website Bonduelle, the vegetable is naturally low in calories and high in fiber, carotene, Vitamin C, and zinc.

The spirals of florets on a Romanesco broccoli form natural fractals. A fractal, stated as simply as possible, is a pattern that looks almost exactly the same at every scale. So if you used your camera and zoomed in tighter and tighter on a head of Romanesco broccoli, every frame would look like the one before it, despite the fact that you were focusing on increasingly tiny segments. Fractal patterns occur throughout nature, including salt flats, spiral seashells, ferns, peacock feathers and snowflakes. To learn more about naturally-occurring fractals, check out Wired’s photo gallery. 

The repeating pattern we see in this vegetable is a spiral, and to make things even more interesting, that spiral is approximately based on a Fibonacci sequence, a series of numbers in which each number is the sum of the two previous numbers.  A Fibonacci sequence looks like this: 1,2,3,5,8,13,21,34,55 and so forth.

As it turns out, a lot of plant life grows in patterns that mimic the Fibonacci sequence with petals, leaves, or (in the case of Romanesco broccoli) tiny buds called “meristems” that have 1,2,3,5,8,21 and more spirals coming from the center. For a truly entertaining and thorough explanation of how the Fibonacci sequence turns into a spiral and why appears throughout nature, Vi Hart’s YouTube videos are a great resource. 

Once you’ve thoroughly studied your broccoli, it’s probably a good idea to eat it. It is just fine eaten raw with dip, or steamed with some lemon and/or garlic. It also roasts well, cut into branches and coated with a little olive oil.

A single Romanesco broccoli flower from the farmers market is a substantial hunk of vegetation, so you may want to plan to halve it or quarter it, and use it several different ways throughout the week. After eating some raw, with hummus, and roasting some as a side dish, I made a cream soup from the rest. Feel free to use any kind of cheese you like, use low fat dairy to reduce calories, vegetable broth to make it vegetarian, and experiment with soy milk and cheese if you’re vegan or lactose-intolerant. Serve with a green salad and some whole grain bread for a filling fall lunch or dinner.

Cream of Romanesco Broccoli and Smoked Gouda Soup

Ingredients: 

• ·        ¼ cup butter
• ·        1/2 onion, chopped
• ·        1/4 cup flour
• ·        2 cups milk (I used 1%)
• ·        2 cups chicken or vegetable  stock
• ·        1 ½ - 2 cups coarsely chopped Romanesco broccoli
• ·        2 1/2 cups shredded, smoked Gouda or other strong cheese (Applewood Cheddar would be nice)
• ·        salt and ground black pepper to taste

Directions:

1. Place broccoli in a microwave-safe dish with two tablespoons of water. Cover and cook on high heat for 5-7 minutes, or until all pieces are fork-tender.
2. Melt butter in a skillet over medium-high heat. Sauté onion in hot butter until translucent, about 5 minutes.
3. Whisk flour into butter and onions over medium-low heat, cooking until flour loses its granular texture (about 3 to 4 minutes).
4. Gradually pour milk into flour mixture while whisking constantly. You are looking for a thick, sauce-like consistency.
5. Once milk and flour are smooth and thick enough to coat a spoon, stir in cheese until completely melted.
6. If you want a smooth soup, use an immersion blender (or regular blender) to combine cheesy mixture and steamed broccoli. If you want a chunky soup just add the steamed vegetable to the cheese sauce and stir to combine.
7. Stir stock into milk mixture.  Cook over low heat until soup is heated through, taking care not to let the milk and cheese burn on the bottom of the pot. Add salt and pepper to taste.

Photo of Romanesco broccoli:  Kent Wang, on Flickr, via Wikimedia Commons.

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