I love cinnamon buns. And I think I’m not alone in that regard — the whole world loves cinnamon buns.
But I’m quite particular about them. In my opinion, there’s only one true way: they must include cardamom and absolutely no glaze (!!). For me, the perfect bun isn’t about overkill; it’s about simple perfection. If you wander down that devious path of glazed cinnamon buns, you’re on your own.

My definition of a good cinnamon bun: a slight crunch on the outside, just enough fat inside, not too sweet but with a generous amount of cinnamon and, as mentioned before, a pinch of cardamom. The perfection is completed with just a sprinkle of coarse sugar on top.
Since I lived for half a year in Finland, maybe I’m biased toward their version of the cinnamon bun, called Korvapuustit. The name roughly translates to “slap on the ear,” supposedly because the shape resembles a swollen ear. I admit that sounds a little unpleasant, but I’ve never quite managed to see the resemblance anyway.

What I haven’t mentioned yet, because it seems so obvious, is the moistness factor. It’s the crucial difference between an “okay” cinnamon bun and a truly great one. Nonetheless is most often the downfall for yeasty bakes. Even when they taste great straight out of the oven, some hours later they begin to stale. At least that’s my experience with cinnamon buns.

But lately I stumbled upon a recipe for Japanese milk bread that uses a technique called Tangzhong. It turns out the solution is a simple flour paste — one that keeps cinnamon buns soft and delightful even the next day.

Recipe

Ingredients

Tangzhong:

• 50 g white flour
• 300 ml milk

Dough:

• Tangzhong
• 500 g flour
• 75 g room-temperature butter
• 75 g sugar
• ½ tsp salt
• yeast (1 packet or ~7 g)
• 1 tsp cardamom
• 25 ml milk

Filling:

I purposely did not give any measurements for the filling, I feel it’s very personal to your likings. Feel free to experiment a bit with it.

• butter
• sugar
• cinnamon
• ½ tsp cocoa powder (optional, for color contrast)

Preparation

1. For the Tangzhong, whisk the flour and milk together in a small pot. Heat while whisking until the mixture thickens slightly. This happens around 65°C, so no need to let it boil.
2. Let the Tangzhong cool for at least an hour, or ideally overnight.
3. For the dough, combine all ingredients and knead until it passes the windowpane test. In my stand mixer, this takes about 5–6 minutes. It might first seem like there isn’t enough liquid to bring the dough together, but trust the process, don’t add more milk!
4. Let the dough rest until doubled in size.
5. Roll out the dough into a rectangle about 1 cm thick.
6. Mix all ingredients for the filling. I like to add a bit of cocoa powder because it gives a nice color contrast to the cinnamon swirls.
7. Spread the filling evenly over the dough.
8. Roll up the dough from the shorter side of the rectangle — this creates more swirls.
9. Cut the roll into trapezoid-shaped pieces and place them with the narrow side facing up. Press each piece down in the middle with your finger to create the classic Korvapuusti shape.
10. Place the buns on a baking tray and let them rise. I like to add a small bowl of boiling water underneath (if proofing in the oven) to create gentle warmth and humidity.
11. When the buns have risen (I find that these buns need a little longer to rise than buns without Tangzhong, mine usually need an hour), remove them from the oven and preheat it to 200°C.
12. Brush the buns with milk and sprinkle coarse sugar on top.
13. Bake for about 15 minutes, or until golden brown.

Why does it work: Tangzhong & Retrogradation

As mentioned above, the true enemy of soft cinnamon buns is retrogradation — in everyday terms, staling.

When you bake bread (or cinnamon buns), the starch molecules absorb water and swell — a process called gelatinization, which gives the crumb its softness. As the bread cools, those starch molecules (amylose and amylopectin) gradually recrystallize (realign into ordered structures) and expel the trapped water. This loss of moisture makes the bread hard and brittle.

A practical side note: this process happens fastest in the fridge, so never store baked goods there. Counterintuitively, the freezer is a much better option, since retrogradation occurs most rapidly between about 0°C and 10°C.

Making Tangzhong (also called water roux) forces some of the flour’s starch to gelatinize fully before the dough is even mixed, allowing it to absorb and hold more water without making the dough sticky. This tightly bound moisture slows the rate of starch retrogradation after baking, keeping the crumb softer for longer.

Additionally, the pre-gelatinized starch is more easily broken down by enzymes into small sugar fragments that don’t recrystallize easily, providing a chemical defense against staling.