Heat up a saucepan over medium heat and when hot, add the olive oil, then sauté the shallots and garlic for 2 minutes until the shallots become translucent.
Add the wine plus herbs de Provence and cook until the wine is reduced by half.
Add the chicken based demi glace or meat based demi glace if you can’t find it. You can also use chicken stock that has been reduced by half. Bring this to a boil and then lower heat to a simmer.
Add the chopped tomatoes, chervil, parsley and some salt & white pepper. Cook for a couple more minutes, taste and adjust seasonings.
When the sauce is thick enough to coat the back of a spoon, it is ready to serve.