Define buildconfigfield for an specific flavor AND buildType

I have 2 flavors, lets say Vanilla and Chocolate. I also have Debug and Release build types, and I need Vanilla Release to have a field true, while the other 3 combinations should be false.

def BOOLEAN = "boolean"
def VARIABLE = "VARIABLE"
def TRUE = "true"
def FALSE = "false"

    VANILLA {

        debug {

            buildConfigField BOOLEAN, VARIABLE, FALSE

        }

        release {

            buildConfigField BOOLEAN, VARIABLE, TRUE

        }


    }

    CHOCOLATE {
        buildConfigField BOOLEAN, VARIABLE, FALSE
    }

I'm having an error, so I guess the debug and release trick doesnt work. It is possible to do this?

Loop the variants and check their names:

productFlavors {
    vanilla {}
    chocolate {}
}

applicationVariants.all { variant ->
    println("Iterating variant: " + variant.getName())
    if (variant.getName() == "chocolateDebug") {
        variant.buildConfigField "boolean", "VARIABLE", "true"
    } else {
        variant.buildConfigField "boolean", "VARIABLE", "false"
    }
}

Here is a solution without lacks I've described under Simas answer

buildTypes {
    debug {}
    release {}
}

productFlavors {
    vanilla {
        ext {
            variable = [debug: "vanilla-debug value", release: "vanilla-release value"]
        }
    }
    chocolate {
        ext {
            variable = [debug: "chocolate-debug value", release: "chocolate-release value"]
        }
    }
}

applicationVariants.all { variant ->
    def flavor = variant.productFlavors[0]
    variant.buildConfigField "boolean", "VARIABLE", "\"${flavor.variable[variant.buildType.name]}\""
}