Simple Supper Friday: Seared Flap Steak with Kale and Mustard Sauce

Seared flap steak with kale and mustard sauce.

I had a wonderful dinner the other night of flap steak with a creamy mustard sauce and a side of sautéed kale. I mentioned this in yesterday’s post, and as promised, am sharing the recipe.

This recipe definitely stands true to simple. The sauce whips up quickly and takes an easy meal to the next level, making it a bit more special. I can’t take credit for the sauce recipe — it comes compliments of Mark Sisson’s cookbook, Primal Blueprint Quick & Easy Meals. I can take credit for how I used it though.

For those unfamiliar, flap steak is a thicker variation of skirt steak. I recently discovered this cut at my neighborhood Whole Foods, and really enjoy it. I figured I’d like it since I love skirt steak so much, and I was right. It cooks fast, but takes a bit longer than regular ol’ skirt steak because it’s thicker. I have a tendency to call it flab steak, and then I catch myself. I think I just like calling it flab steak better. Flab steak does not equal flabby either!


  • 1 small shallot, sliced
  • 2 Tbsp butter, preferably grass-fed or organic
  • 1/2 cup chicken broth
  • 1/4 cup full-fat coconut milk
  • 1/2 cup Dijon mustard
  • 1/2 Tbsp dried parsley or 1 Tbsp finely chopped fresh parsley
  • 1 lb flap steak, preferably grass-fed (you can use skirt steak as an alternative)
  • 1/2 – 1 Tbsp fat of choice (I used ghee)
  • Sea salt and pepper to taste
  • 1 bunch of kale, stemmed and chopped

Mustard sauce.


  1. Melt the butter in a small skillet or saucepan over medium heat. Add the shallot and sauté a few minutes, until softened.
  2. Add the chicken broth and simmer for five minutes. Then, add the mustard and coconut milk and simmer for two minutes more. Stir in parsley and set aside. The recipe makes about 1/2 cup of sauce.
  3. Season flap steak with sea salt and pepper. Melt fat of choice in a large skillet over medium-high heat. Once pan is hot, add the flap steak and cook about five minutes each side for medium doneness. Keep a close eye on it though because the thinner ends will cook quicker. If you’re using regular skirt steak, go with three minutes per side. If you like it more done or rare, then adjust accordingly.
  4. Once meat is done, remove from pan and set aside to rest for 10 minutes before slicing.
  5. Meanwhile, add a bit more fat of choice to the pan that the meat cooked in, over medium-low heat. Add the kale and season to taste with sea salt and pepper. Sauté for a few minutes, until softened.
  6. Thinly slice the steak and serve alongside kale. Top the steak with the mustard sauce and enjoy.

Total time: 20-25 minutes

Yields: 2-3 servings (for us, it was 2 servings plus leftover sauce)



8 thoughts on “Simple Supper Friday: Seared Flap Steak with Kale and Mustard Sauce

  1. Megan December 14, 2012 / 7:30 am

    Great recipe! I love using mustard to spice things up! I found a local farm here that makes a Bavarian Beer Mustard, it has the whole seeds and all. I bet it would be awesome with this recipe! Just need to restock : )

  2. paleoinpdx December 14, 2012 / 8:46 am

    Thanks! What makes mustard Bavarian Beer Mustard? Is there actual beer in it or is it just meant to complement beer? I’m guessing there’s not beer in it since you don’t eat gluten/grains…

  3. Jill December 15, 2012 / 5:50 am

    Hi, looks good.
    I’ve been eating salmon 2-3 times per week. It’s wild. I’m never in the mood for it (HUGE fillets) but they’re there and my mom wants them, so its “convenient”. She said to put on parchment paper in baking dish, sprayed with lemon juice and bake for 1.5 hours. Seems like a LONG time to bake. Granted they are big fillets (definitely 6.5-8.5 ounces each. But still, thoughts on how long to truly bake them? And just spritz with lemon juice? Thanks.

    • paleoinpdx December 15, 2012 / 7:37 pm

      Hey Jill, wild salmon is great, but if your mom is cooking it for 1.5 hours, I don’t know how it can taste good. It seems like it’d be really dry. What temp is she baking it at? Regardless, that is a really long time! When I’ve made salmon, it bakes for under 20 minutes, about 18 I believe. Feel free to Google baked salmon recipes as well and see what other recipes suggest. I don’t use baking spray, but like a little butter and lemon juice is good too. It really doesn’t need much to taste good.

      • Jill December 16, 2012 / 9:52 am

        Thanks. That’s “her” way…odd. I cooked mine for 40 mins and it was flaky soft …but it was HUGE cause I am ridiculous and eat all 8 oz at once…oh my.

        It worries me though that she said she got them at Costco in town (2 hours away is the real “city” 😦 ) and the bag said “frozen wild salmon fillets”. She threw them out so I have no idea what they really are..all I know (from her) is that they are wild frozen salmon fillets from Costco.
        The food quality thing here very very much bugs me. I have about 4 meals of wild moose left (froze it). Mom roasted it in the oven for several hours. I am not sure how OFTEN I should eat it a week since it is technicaly a “red meat”.
        As for the chicken, the kind my mother just roasted in the oven (with the SKIN ON, meaning the hormones/toxins must soak thru it while cooking myabe) is this : . Or there’s this:
        See, I feel VERY uncertain about touching that stuff…
        I’m so mixed on the quality of the food here. I’m feeling very confined and frustrated (SO frustrated).
        Okay, I will stop bugging you now. Promise.

      • paleoinpdx December 16, 2012 / 11:05 am

        The salmon sounds just fine. There’s nothing wrong with it being frozen. It’s still wild salmon and that’s what matters. Also, it’s totally fine that you ate the whole fillet. I’d eat it all too! Why are you so worried? Costco is fine for picking up various things. I don’t shop there because I don’t have a membership, but I know you can find some quality products there.

        Also, it’s totally fine for you to eat red meat everyday if it’s high quality, like the moose. Again, no worries! The red meat myth is total hogwash anyway, though it is good to vary your proteins. If you have access to the moose right now, there’s nothing wrong with eating it regularly and everyday. Take advantage of it while you can! If you’re skeptical of the chicken, don’t eat it or remove the skin and fat before eating, even it’s already been cooked. The chicken is grain-fed, which is not ideal, but if it’s the best you can do, then I’d say just eat it once in a while and remove the skin/fat. Feel free to reach out to the manufacturer and ask it it’s hormone/antibiotic free as well. I didn’t see it labeled as so, but your labeling policies may be different than ours in the U.S.

        Anyway, hope that helps.

  4. Jill December 17, 2012 / 5:44 am

    Thanks. You are patient.
    My father told me he caught a rabbit. He cooked up it up but I’m wary of HOW he cooked it, so I might ask him to give me the next one UNCOOKED. I have NO IDEA what rabbit tastes like or if it is a worthy “meat” at all…or how to cook it SAFELY …I’ll have to research. Not sure I’d even like it.

    • paleoinpdx December 17, 2012 / 11:42 am

      Yes, rabbit is a worthy meat. I haven’t had it since I was a little kid (my dad rabbit hunts), but remember it tasting like chicken. Give it a try … you might like it 😉

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