Heat oil in a large non-stick frying pan on medium high. Crack eggs one at a time into hot pan. Cook for 2 minutes, until whites set and are crispy around the edges

Split croissants in half and place cut-side up on an oven tray lined with baking paper. Cook under grill for 30 seconds to 1 minute, until toasted and golden

In a small bowl, combine crème fraiche, chives, lemon zest and juice. Season with salt and pepper and mix well

Spread bases with crème fraiche mixture. Top with watercress, folds of trout slices and then a fried egg. Scatter with extra chives and pepper. Serve with lemon wedges and any extra crème fraiche mixture