70 gm(¼ cup) Dijon mustard1 tbspfinely chopped flat-leaf parsley, plus extra to serve2 tsp eachfinely chopped thyme, rosemary, chives and tarragon, plus extra to serve1garlic clove, finely chopped1 tbspolive oil4 piecesbeef fillet (200gm each), at room temperature80 mldry white winePeas à la Française1½ tbspolive oil1small onion, finely chopped2bacon rashers, diced½garlic clove, finely chopped80 mldry white wine250 ml(1 cup) chicken stock2thyme sprigs1baby cos lettuce, coarsely chopped200 gmfrozen peas
Preheat oven to 220C. Stir mustard, herbs and garlic in a bowl to combine, season to taste and set aside.
For peas à la Française, heat oil in a deep frying pan over medium-high heat, add onion, bacon and garlic and sauté until onion is tender and bacon begins to crisp (4-5 minutes). Deglaze pan with wine and simmer until reduced by half (1-2 minutes). Add stock and thyme and simmer to develop flavours (4-5 minutes). Add lettuce and peas, season to taste and simmer until lettuce and peas are just tender (4-5 minutes).
Meanwhile, heat oil in a large ovenproof frying pan over medium-high heat, add beef and brown well all over (3-4 minutes). Pat beef dry with paper towels, brush with half the mustard mixture, return to pan, transfer to oven and roast until cooked to your liking (4-5 minutes for medium-rare). Set aside to rest for 5 minutes. Deglaze pan with wine and reduce by half (1-2 minutes). Whisk in remaining mustard mixture and a couple of spoonfuls of pea-braising liquid and season to taste. Serve beef with peas à la Française, spoon pan juices over and scatter with extra herbs.