Maple mustard chicken casserole with roasted root vegetables (low FODMAP)

This is the kind of dinner I make when the oven is doing most of the work and I don’t want to think too hard about it. Chicken thighs go in on top of parsnips, carrots and sweet potato, everything bakes in a mustard and maple stock that thickens into a light sauce, and you get one dish to wash at the end.

It also happens to be low FODMAP, which is the part people usually ask about. No onion, no garlic cloves, no wheat flour. The flavor still holds up, mostly because mustard and maple syrup do a lot of heavy lifting once they cook down with the pan juices.

Why it works without onion and garlic

Two swaps carry the whole recipe.

Garlic infused oil gives you garlic flavor without the fructans that cause trouble, because those compounds don’t dissolve into oil. You get the taste, not the fallout. Buy it or infuse your own, but if you infuse your own, keep it in the fridge and use it within a few days.

The green leaves of a leek work the same way the white bulb would in a normal casserole, minus the FODMAPs. The bulb is the part to avoid. The dark green tops are fine, and they soften nicely if you give them a minute in the hot pan with the chicken.

One thing worth checking: sweet potato is low FODMAP in a small serving, roughly half a cup, and tips over into a moderate mannitol load past that. Spread across four servings, this recipe stays under that line. If you’re mid elimination phase, verify portions in the Monash app, since their testing gets updated.

Ingredients

For the chicken:

• 1.3 lb (600 g) boneless, skinless chicken thighs
• 2 tsp olive oil
• 1 cup (80 g) leek, dark green leaves only, thinly sliced
• Salt and black pepper

For the casserole base:

• 2 large parsnips (about 10 oz / 300 g), peeled
• 2 to 3 large carrots (about 10 oz / 300 g), peeled
• 1 1/2 cups (240 g) sweet potato, peeled and cut into bite sized pieces
• 1 1/2 tbsp garlic infused olive oil
• 3 tbsp gluten free all purpose flour
• 1 1/2 cups (375 ml) low FODMAP chicken or vegetable stock
• 1 tbsp Dijon mustard
• 1 tbsp pure maple syrup
• 1/2 tsp dried thyme
• 3 cups (90 g) baby spinach, roughly chopped
• Salt and black pepper

Kabocha or buttercup squash stands in for the sweet potato with no change to the timing. Regular potato works instead of parsnip if parsnip isn’t your thing, though you lose some of the sweetness that plays off the mustard.

Instructions

1. Heat the oven to 400°F (200°C), or 350°F (180°C) on convection. Grease a large casserole dish.
2. Cut the parsnips, carrots and sweet potato into small, evenly sized pieces and put them in a big bowl. Add the garlic infused oil, scatter the gluten free flour over the top, and season with salt and pepper more generously than feels right. The flour is what thickens the sauce later, so make sure every piece is coated. Tip it all into the casserole dish.
3. Whisk the stock, Dijon and maple syrup together in a measuring cup, then pour it over the vegetables.
4. Put the dish in the oven and set a timer for 30 minutes. The root vegetables need this head start, otherwise the chicken overcooks while you wait on the parsnips.
5. While that happens, heat the olive oil in a large skillet over medium high. Season the thighs and sear them 3 to 4 minutes per side, just until the outside colors. They should not be cooked through. Throw the sliced leek greens into the pan for the last minute so they pick up some of the fat, then take everything off the heat.
6. When the timer goes, nestle the chicken and leek on top of the vegetables and sprinkle the thyme over the whole dish. Back into the oven for 10 minutes.
7. Add the chopped spinach, then bake another 10 to 15 minutes, until the vegetables give easily to a knife and the chicken reads 165°F (74°C) at the thickest part.
8. Check the sauce. If it’s still thin, stir 1 to 2 tsp cornstarch into 2 tbsp cold water, mix it through the liquid, and give it five more minutes in the oven. Serve warm, straight from the dish.

Make ahead and leftovers

You can peel and cut all the vegetables the day before and keep them covered in the fridge. The sauce mixture can be whisked ahead too.

Leftovers keep about three days refrigerated. Reheat covered at 325°F (160°C) rather than in the microwave if you can, since the chicken dries out fast. The sauce thickens overnight, so a splash of stock brings it back.

Freezing is possible but the sweet potato goes mealy. If you plan to freeze it, cut the sweet potato larger than the rest.

Nutrition

Per serving, based on four servings:

High in protein and fiber, low in saturated fat and salt. Figures are estimates and shift with the cut of chicken and the stock you use.

Questions people ask

Can I use chicken breast? Yes, but skip the sear and add it later, around the 40 minute mark, or it turns to cardboard. Thighs are more forgiving in a long bake.

Is store bought stock low FODMAP? Often not. Most contain onion or garlic. Read the label or use a certified low FODMAP brand.

Why gluten free flour if I’m not celiac? No reason, use regular all purpose flour at the same quantity. The gluten free version is there because a lot of people following low FODMAP are also avoiding wheat.

Can I skip the maple syrup? You can, and the dish still works, but it gets sharper. The syrup rounds out the mustard rather than making it sweet.