Generously eason meat with salt & pepper

Sous vide at 130 degrees for 1.5 - 3 hours

Let rest on paper towel for 5 minutes, then thoroughly dry

Sear steaks for 1 minute per side

Reduce heat to MEDIUM

Pour off all oil except 1 Tbsp

Add shallot and fennel seeds for 2 minutes

Add chicken broth, white wine and mustard until reduced to 1/2 cup, about 6 minutes

Stir in cold butter, 1 tablespoon at a time, until melted

Add tarragon