Add the mascarpone, bacon and bacon fat to a bowl and whisk until combined. Slowly pour in the Base Vinaigrette, vigorously whisking to blend smoothly, until completely combined. Taste and season with salt and pepper if needed.
Serve with salads and crudite, as a French fry dip or as a spread for a sandwich.
In a medium mixing bowl, whisk together the vinegar, shallots and 1 teaspoon water. Slowly stream in the oils while whisking. Season with salt and pepper.