I love Japanese curry, and I grew up eating it almost every week. It’s comforting, rich, a little sweet, a little savory, and always hits the spot. And to be totally honest, I mostly cook it straight from the box. Those Japanese curry blocks are popular for a reason.
That said, I am constantly asked for a homemade Japanese curry roux recipe since a lot of people don’t like the fat source from boxed curry roux. Most store-bought curry roux uses vegetable oils or canola oil, which some people prefer to avoid. After enough requests, I decided to finally sit down and make a homemade Japanese curry roux using butter as the only fat. No seed oils, no canola – just butter, flour, spices, and seasoning.
The key thing to understand with this recipe is that it’s a true roux. That means you don’t mess with the fat and flour ratio. It’s a 1:1 ratio. That balance is what gives you proper thickening, a smooth texture, and that classic curry block behavior when it melts into the sauce. Once you get that right, everything else is just flavor tuning. And you can definitely switch a few things around to your liking!
This homemade version isn’t meant to be “health food,” and it’s not trying to reinvent Japanese curry. It’s meant to feel familiar, rich, and deeply comforting – just made at home, with butter doing all the heavy lifting. And a quick note: once you’re done with the roux and ready to make curry, note that you will need to add a few ingredients to get a classic Japanese curry flavor. I’ll list them all out in the recipe. Let’s get started!
Ingredients:
Below is a breakdown of each ingredient and its role in the recipe. The ingredients are divided into two categories: those used to make the curry roux itself, and those added later when cooking the curry using the roux.
Note that if you can’t find some of these ingredients in your grocery store or local Asian market (which I’d be surprised if you couldn’t at both of them!), you can always buy them online. I’ve linked them for your convenience!
- Unsalted Butter: The sole fat source in the roux, providing richness and structure while allowing precise control over seasoning.
- All-Purpose Flour: Combines with the butter at a strict 1:1 ratio to form the roux that thickens the curry smoothly.
- Curry Powder: Supplies the main curry flavor with warmth and spice typical of Japanese-style curry.
- Garam Masala: Adds aromatic depth and complexity that rounds out the curry powder.
- Salt: Seasons the roux itself while leaving room to adjust salinity later when cooking the curry.
- Cayenne Pepper: Provides adjustable heat without altering the overall flavor profile. Feel free to add more or less (or even omit it!) depending on your spice level preference.
- Water: Acts as the liquid base that dissolves the roux and determines the final thickness of the curry.
- Honey: Adds gentle sweetness to balance the savory spices and richness of the butter.
- Soy Sauce: Contributes umami, saltiness, and color for a more developed flavor.
- Worcestershire Sauce: Delivers acidity, sweetness, and fermented umami that helps the curry taste complete.
- Chicken, Potatoes, Carrots, Or Other Add-Ins: Provide substance, texture, and classic curry heartiness.
How to Make the Roux:
- Melt butter in a pan over medium heat.
- Add flour and stir continuously until fully combined.
- Cook until caramel-colored, stirring constantly to develop flavor.
- Add spices (curry powder, garam masala, salt, and cayenne) and mix well.
- Transfer to a lined container and refrigerate overnight to harden.
- Cut into 1 oz cubes once firm, ready for use in cooking curry.
Homemade Japanese Curry Roux
- Total Time: 25 minutes
Description
A rich, comforting Japanese-style curry made with a homemade butter-based roux that melts into a smooth, savory sauce with balanced sweetness, depth, and warmth.
I highly recommend using a scale for this recipe. If you do not own one, you can get by, but it does make this recipe a little easier to ensure that you have an exact 1:1 ratio of butter to flour!
Ingredients
- 226 g (8 oz) unsalted butter (~2 U.S. sticks of butter)
- 226 g (8 oz) all-purpose flour (~1 7/8 cups)
- 1/2 cup curry powder
- 2 tbsp garam masala
- 3/4 tbsp salt (adjust later when cooking the curry)
- 1/2 tbsp cayenne pepper (add more or less depending on spice preference – or omit completely)
- 2 oz curry roux (2 cubes)
- 1 1/2 cups water (adjust for thickness)
- 1/2 tbsp honey (add more for a sweeter curry)
- 1 tbsp soy sauce
- 2 tbsp Worcestershire sauce
- Salt, to taste
- Cooked diced chicken, potatoes, carrots, or other toppings of choice
Instructions
To make the curry roux:
- In a pan over medium heat, melt the butter completely. Add the flour and stir continuously until fully combined.
- Continue cooking, stirring constantly, until the roux deepens into a darker caramel color. Take your time here – it could take about 15 minutes.
- Add the curry powder, garam masala, salt, and cayenne pepper. Stir well to evenly distribute the spices, then remove from heat.
- Transfer the roux to a container lined with parchment paper or a silicone mold (I used Souper Cubes). To make portioning easier later, I like to divide the roux into ½-cup portions, which work out to about 4 oz each.
- Refrigerate overnight until fully hardened.
- The next day, once firm, cut the roux into 1 oz cubes (if you divided the roux into ½-cup portions, you just need to divide these into fourths). This recipe yields about 16 oz total.
To make the curry:
- Add the water to a pot and bring to a gentle simmer.
- Add the curry roux cubes and stir until completely dissolved.
- Stir in the honey, soy sauce, and Worcestershire sauce. Taste and season with a little salt if needed.
- Add cooked diced chicken, potatoes, carrots, or other toppings. Simmer until everything is heated through and the vegetables are soft.
- Add a splash of water if needed to loosen the curry to your preferred consistency. Serve hot!
Notes
Frequently Asked Questions:
Can I use salted butter instead of unsalted?: Yes, but reduce the added salt in the roux and adjust seasoning when cooking the curry to avoid over-salting.
How long does the curry roux keep?: The roux will keep for 2 weeks in the refrigerator or up to 6 months in the freezer when stored in an airtight container.
Can I freeze the roux?: Yes – freezing works very well. Freeze the roux in pre-portioned cubes so you can use exactly what you need. Store up to 6 months.
Why does the butter and flour need to be 1:1?: A 1:1 ratio by weight creates a stable roux that melts smoothly and thickens the curry properly; changing the ratio can affect texture and consistency.
My curry is too thick – how do I fix it?: Simply add more water a little at a time while simmering until you reach your preferred consistency.
My curry tastes flat – what should I adjust first?: Start by adjusting Worcestershire sauce or soy sauce, then sweetness (honey or apple), and finally salt.
Is this meant to be healthier than boxed curry?: This recipe isn’t about making curry “healthy” – it’s about controlling ingredients and using butter instead of vegetable or canola oils.
- Prep Time: 5 minutes
- Cook Time: 20 minutes
Nutrition
- Serving Size: 8
Added grated apples and a square of chocolate like my obachan always did and this was perfect! Thank you for the recipe!
Wow that was fast – thanks for trying my recipe, Maya! Glad you enjoyed it and customized it 🙂