Bring the butter to room temperature and mix in the chopped tarragon and shallot.
Roll the butter into a tube shape and place in fridge.
Place each chicken breast on a board and, using a shape knife, cut a pocket into each breast.
Place the breadcrumbs on a plate and beat the egg in a bowl.
Remove the butter from the fridge and cut into slices, then place the slices into the pocket of the chicken breasts.
Dip each breast first into the egg, then roll in breadcrumbs until covered.
Heat the oil in a frying pan and fry each side of the chicken breasts for 2-3 minutes.
Once sealed place in a preheated oven at 200C for 20 minutes.
Serve with a lightly tossed green salad and new potatoes.
Any left over butter can be kept in the freezer for future use. The tarragon butter also goes well melted over a steak.
Please note: this recipe has been created and uploaded by a member of the Tesco Real Food online community. Tesco does not test customer recipes so cannot accept responsibility for the content, validate the results or answer queries regarding them.