Coconut Mung Bean Pie

Growing up, my family would get together every Sunday to share a traditional Cantonese style dinner at Sea Empress, the only decently authentic Cantonese restaurant in our neighborhood of LA. Dinner always looked something like this: a braised green veggie like bok choy or gai lan (Chinese broccoli), a whole steamed fish dressed with scallions and ginger, a stir-fried noodle dish of some sort, crab, lobster, or shrimp depending on the season, and roasted or boiled chicken.

I was never involved in ordering decisions because 1) I was a child and 2) I didn’t speak Cantonese. I’d sit mostly quietly and wait for food to show up on my plate, shoveled eagerly by my uncle or grandma. Dessert was an even bigger roll of the dice: mango pudding and almond jelly with sago were my favorites but those were rare offerings. More often than not dessert was some kind of a hot, sweet, bean-based soup. Red bean was the most common, and therefore the bane of my existence. I hated (and still don’t love) the texture of the skins and the earthy flavor. It never scratched the itch of a true *dessert*. On rarer occasions we’d be treated to hot or cold green bean (AKA mung bean) soup, which I greatly preferred to its red bean cousin.

In western countries, mentioning “beans” rarely conjures up thoughts of sweet treats, but Asian kids all around the world know intimately the range beans can offer beyond just chili, daal, and the occasional salad.

Mung beans in particular are an unsung hero (in my humble opinion) of the Asian dessert world. They appear most commonly in southeast Asian desserts like Vietnamese chè, the aforementioned Cantonese green bean soup, and pressed mung bean cakes, but they also show up in both savory and sweet applications throughout the continent.

Recently, I was experimenting with mung beans in both familiar and unfamiliar applications and realized that when steamed, then pureed and cooled, mung beans take on a texture not dissimilar from cooked sweet potato. I immediately wondered why mung bean pie isn’t a thing and set off to develop my own*.

*Quick caveat here that yes, there are of course pie-like desserts in Asia stuffed with mung bean like Filipino hopia and Chinese “wedding pies,” but I wanted to make an American style pie that featured mung bean as its star.

My first couple tries at this pie were unsuccessful. Unlike sweet potatoes and other typical pie ingredients, mung beans contain a large amount of starch (which is why they’re used for things like mung bean jelly noodles) that I found difficult to work with. The mung bean custard set much firmer than I wanted and it took some trial and error to get the flavor and texture balance just right. In the end I’m happy to say I think I accomplished what I was looking for, almost to a T.

I’ve posted quite a few videos about mung beans at this point and a few people have asked me what they taste like, which is a very reasonable question. The problem is that I’m not sure how to describe the taste to someone who hasn’t had them. Like most legumes, they have a slight earthy flavor, but there’s something distinctive about a mung bean that sets it apart from red bean. This earthiness pairs extremely well with coconut and pandan flavors, so you’ll often find 2-3 of this trio combined into many mung bean-centric recipes.

This pie is no different. When I gave a slice to my dad and my uncle without telling them what it was, they both got extremely frustrated trying to figure out what they were tasting. They both knew it was super familiar but couldn’t quite put their finger on it. That’s exactly what I wanted to capture with this pie, which is a sort of fusion of my western baking background and my Asian dessert preferences. The coconut, pandan, and mung bean flavors marry together super harmoniously, while a little extra salt in the whipped cream topping and the addition of sago on top add some extra dimension and texture.

A few notes on this recipe to really nail it:

The Crust

I initially tried to make a cornflake crust for this pie because I thought a slightly corny flavor would pair nicely with the filling ingredients. While I think my flavor hunch was in the right place, I just couldn’t get the texture to cooperate no matter what I tried. Cornflakes are hard to grind into a fine crumb which makes them susceptible to moisture leaks, which in turn makes them get soggy quickly. Eventually I realized I had to find another pairing.

I immediately thought of the barely-sweet British-style coconut biscuits I grew up eating at my grandma’s house. I’m not sure of the brand, but I think they still sell them at 99 Ranch and other Asian markets — I need to do some digging.

Either way these biscuits can best be likened to a sweeter Ritz-style cracker with a hint of coconut flavor. Since I didn’t have any on hand, I went to the store to investigate what could get me close. I locked onto a biscuit I’ve never seen before called “Leibniz Butter Biscuits” that looked super similar to the coconut biscuits of my youth so I grabbed a pack of those along with some Nilla wafers, Club crackers, and graham crackers as backup.

Once I ground up the butter biscuits and mixed them with coconut oil (for that slight coconut flavor) and sugar, I knew I had found a very close dupe. For any Hong Konger kids, this flavor should be super nostalgic, and it’s a pie crust flavor I’m going to be using much more often from now on.

Be sure to use unrefined or virgin coconut oil, which retains some coconut flavor unlike refined coconut oil which is mostly neutral in taste.

The Filling

Technically this is a custard pie, but it doesn’t behave exactly as you might expect if you’ve had a lot of experience with custard pies. This is because of the high starch content mentioned earlier. Mung beans also readily absorb water and expand quite a bit, adding another layer to the challenge.

Split peeled yellow mung beans are the same thing as green beans (as in Chinese dessert green beans, not to be confused with American green beans which are long and skinny), but as the name suggests, they have been peeled and split. They lose some of their fiber when the skin is removed but they’re still a good source of protein.

When making this pie be careful to not over-bake the filling — it will still be jiggly when you remove it from the oven (more so than a cheesecake or key lime pie, if you’ve ever made one of those), but it will firm up a ton as it cools.

Full fat coconut milk is important for making sure this pie has enough richness. Mung beans are high in protein and carbohydrates but lack much fat — a necessary ingredient for any good dessert. For the best flavor and texture you’ll also want to make sure you use high quality coconut milk. I prefer coconut milk with no gums or other additives. The two brands I’ve found that are easiest to get ahold of are Chaokoh and the Trader Joe’s Organic coconut milk variety.

Pandan is a specialty ingredient of southeast Asian origin. If you’re lucky enough to live by a southeast Asian market, you can probably track this down in the frozen section. If not, you can use a few drops of pandan extract instead, which is available online (just use it sparingly, as it’s quite strong in both flavor and color).

A Note on Bean Pies

In doing some research for this recipe, I learned that African American Muslims have been making a “navy bean pie” for decades. Unlike this pie, traditional navy bean pie is closer in flavor to a sweet potato pie, featuring warming holiday spices like cinnamon. This pie has a super interesting history rooted in anti-slavery but I don’t think it’s my story to tell. It’s worth looking up and I definitely plan on trying my hand at a navy bean pie soon!