Add oil to empty skilled used to cook chicken and return pan to low heat.
Add shallot and cook, stirring often, until softened,
Add flour and cook stirring constantly for 30 seconds.
Add broth, increase heat to medium high and bring to simmer, scraping pan bottom to loosen browned bits. Simmer rapidly until reduced to 1/2 cup. Stir in any accumulated chicken juices, and return to simmer and cook for 30 seconds.
Turn off heat, and whisk in lemon juice, capers, parsley and butter, season with salt and pepper.