Tri-tip is a flavorful cut of meat from around the sirloin region. It is usually grilled and cut across the grain to help make it more tender and with sous vide it can benefit from extended cooking times. I like to pair it with a rich, flavorful salad of oranges and roasted fennel.
The longer you cook tri-tip the more tender it will become, so you can choose your time according to what you are trying to accomplish. For a more traditional texture you can cook it for 3 to 4 hours. Eight hours will give you a more tender, but still toothy result and 24 hours will result in super tender meat. I usually prefer somewhere in the 10 to 12 hour range.
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Preheat a water bath to 131°F (55°C).
Mix together the spices in a bowl. Lightly salt and pepper the tri-tip then coat with the spices. Place the tri-tip in a sous vide bag then seal. Cook for 10 to 12 hours.
For more information on the cooking times you can read my detailed article which addresses why is there a range in sous vide cooking times.
Preheat an oven to 400°F (204°C).
Remove the fronds from the fennel and set aside for later. Cut the fennel into large chunks. Toss the fennel with the garlic and half of the olive oil, then salt and pepper it. Roast the fennel in the oven for 45 to 60 minutes, until tender and cooked through. Remove the fennel from the oven.
Over a bowl, cut the orange into supremes by slicing off the peel and pith, then cutting out the segments between the membranes. Set the supremes aside and squeeze out any remaining juice from the leftover flesh on the orange.
Zest the lemon and set the zest aside for later. Quarter the lemon and squeeze half of it into the orange juice. Whisk in the remaining 1/4 cup of olive oil until it forms a vinaigrette.
Combine the fennel, orange supremes, shallots and olives then toss with the dressing. Mix in half the herbs then sprinkle the other half on top along with the lemon zest. Chop some of the reserved fennel fronds and sprinkle on top.
Remove the tri-tip from the sous vide bag and pat dry. Quickly sear until just browned. Remove from the heat and slice it into 1" (25mm) slabs.
Serve the slices of tri-tip with the fennel and orange salad.
To help the sauce cling to the fennel I will usually add xanthan gum to it. Just blend in 0.15% xanthan gum to the orange juice and olive oil before combining the dressing with the vegetables.