Preheat the oven to180°C (350°F).
Finely chop the shallots.
Coat the pork tenderloins with flour.
In a frying pan, heat some fat (butter, oil or a mixture of both), then, brown the pork tenderloins on all sides. Once they are golden brown, remove them from the pan and set them aside.
In the same pan, saute the shallots for 1 minute (if necessary, add some more fat). Then, add the mustard and the maple syrup. Add salt and pepper. Let the sauce thicken for about 5 minutes.
If you are using an oven-safe pan: put the pork tenderloins in it and coat them well with the sauce.If not, transfer the pork to an oven-safe dish and pour the sauce over it.
Take it to oven for about 25 min.