Lava Cake Lessons in Math
You might wonder what lava cake has to do with math. I’ll explain, but first you need to know about my tumultuous relationship with numbers.
I confess that I didn’t do well in math as a youngster. In fact, even though I scored in the 13th percentile in math on my ACT (or maybe the SAT), my university somehow overlooked that fact (maybe because I scored in the 98th percentile in English?).
My second quarter of college, I asked my friends which math class I should enroll in. They suggested precalculus. I failed to tell them that I had only had a year and a half of math in high school. They didn’t ask, either—maybe because most of them had entered the engineering program and they assumed that everyone did math well.
The only thing I recall from precalculus is the professor’s quirky habit of tapping the chalkboard with the knuckle of his middle finger and saying, “It’s obvious to the most casual observer that the answer is—!”
This frustrated me to no end, because I classified myself as a casual observer and NOTHING made sense. I dropped the class after failing the first exam.
My junior year, my friends suggested that perhaps I should try fundamentals of math. I enrolled, eager to have my one required math class out of the way.
Despite spending hours at the tutoring center, I still failed the first test. And the second. On the last day to drop classes, I finally figured out that the professor had left READING assignments for us in his class syllabus. READ a MATH textbook?! The thought had never occurred to me. No wonder I felt lost in class and always five steps behind everyone else!
I dropped the class and determined to read the math textbook next time. My last quarter of college, I enrolled in math for liberal arts majors—and passed. Barely.
I managed not to miss my lack of math skills for another four years—until faced with an exam I had to take to make myself eligible for a California teaching license. I borrowed my little sister’s college algebra textbook and spent three months one summer reading it through. I did the odd-numbered problems every few pages and checked my work at the back of the book.
When the test results came back, to my great disgust, I discovered that I scored higher on math than I did on writing! But I passed, and I put math behind me for the next 26 years.
Math in Real Life
During pre-session last August, I discovered that I would have to act as a math assistant. I really wanted to work with the kids doing third grade math. I figured I could handle that. Instead, I got the fourth-grade group.
Fortunately, the kids use a self-paced computerized math program, and my job would entail printing off assignments and verifying test readiness. I could do this. But then I discovered that they needed help understanding the concepts. I would print out the worked examples, try to make sense of them, and then explain it to a student. Shockingly, they learned! I did, too. They (and I) have made it through fourth and fifth grade math already this year. Half of them just started seventh grade math.
Forty years after ‘learning’ this stuff in elementary school, I finally see the point. Especially when it comes to the kitchen. I guess that makes me a lifelong learner.
Ever since I started cooking and baking at the tender age of seven, I have needed to double or triple recipes. Sometimes, I needed to cut them in half, too. I used a complicated system of measuring cups and teaspoons and logic to more or less accomplish my kitchen math.
I’ve stubbornly stuck to my system until this year, when I relearned (or maybe really learned for the first time), how to divide and multiply fractions. In fact, this week I used my new skills to figure out the proper proportions for making lava cake for six people (instead of four).
I’ll show you how easy it is to convert the recipe using actual math (and not just extra measuring implements). First, I’ll give the recipe, then I’ll explain the math. And yes, I know I could have just doubled the recipe, but I didn’t, for two reasons. I wanted to use my newly relearned math skills and I didn’t want two extra servings of lava cake calling my name.
Chocolate Lava Cake
4 servings (6 servings)
2/3 cup semi-sweet chocolate chips (1 cup semi-sweet chocolate chips)
½ cup butter (¾ cup butter)
1 cup powdered sugar (1 ½ cups powdered sugar)
¼ cup cocoa powder (3/8 cup cocoa powder)
2 eggs (3 eggs)
2 egg yolks (3 egg yolks)
6 Tablespoons whole-wheat flour (9 Tablespoons of whole-wheat flour, same as 1/2 cup flour +1 Tbs)
Dash of salt (Pinch of salt)
- Preheat oven to 425 degrees.
- Butter and flour (I use whole-wheat flour for this, too) four (or six, depending on which recipe you use) custard cups and place them on a cookie sheet. I have also used the baking spray that has flour in it.
- In a microwave-safe bowl, place the butter (unwrapped) and pour the chocolate chips on top. Microwave on high for 45-60 seconds.
- Stir until chocolate melts completely.
- Stir in the cocoa powder and sugar and mix until well-blended.
- Whisk in the eggs and egg yolks.
- Stir in the flour (you can blend the whole-wheat flour in a blender for 30 seconds to make it finer).
- Divide evenly between the four (or six) custard cups.
- Bake for 13-15 minutes—until the sides are firm and start to pull away from the edge of the custard cups, but the middle still looks soft.
- Let stand one minute.
- Invert the custard cup over a serving plate (you may need to loosen the sides with a flexible knife, first).
- Serve immediately with raspberry sorbet and lime wedges, or vanilla ice cream.
You can prepare these a day ahead and leave them covered in the refrigerator until about an hour before you’ll need them. They will warm up to room temperature and be ready to pop in the oven when you sit down to dinner.
Math Principals for Multiplying Fractions
Ok, let’s say the recipe will serve four people, but you have six coming over for dinner. You will need one and a half of the recipe. In order to accomplish all of the multiplication, you’ll need to convert 1 ½ into a fraction (it’s a mixed number when it’s 1 ½).
To turn 1 ½ into a fraction, you have to first turn the whole number (the 1) into a fraction. Simply write it as 2/2 (you keep the same bottom number as the fraction to the right of the whole number). Now, you add 2/2 + ½. When you add fractions, you don’t change the bottom number, you just add the top number. The answer is 3/2 (so if you ask yourself, “How many times does two go into three?” the answer would be, “one time, with ½ leftover, or 1 ½ times).”
To multiply your measurements by 2/3, you’ll need to first turn each of the whole numbers into a fraction, and then multiply the top numbers by the top numbers and the bottom numbers by the bottom numbers. Once you have the results, you’ll need to reduce the fraction (turn it into its most measuring-cup form).
Q4U: What about you? Did you struggle with any subjects back in elementary or high school (or college!)? Have you tried relearning those subjects lately?
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