I claim the ornamental design for an adjustable flame fondue burner, as shown and described.
FIG. 1 is a perspective view of the adjustable flame fondue burner, the broken lines showing portions of a fondue pot that form no part of the claimed design.
FIG. 2 is a top view of the adjustable flame fondue burner.
FIG. 3 is a bottom view of the adjustable flame fondue burner, the broken lines showing portions of the article that form no part of the claimed design and with the portions of the fondue pot shown in broken lines in other figures being removed.
FIG. 4 is a right side view of the adjustable flame fondue burner, the broken lines showing portions of a fondue pot that form no part of the claimed design, and the left side being a mirror image.
FIG. 5 is a front view of the adjustable flame fondue burner, the broken lines showing portions of a fondue pot that form no part of the claimed design; and,
FIG. 6 is a back view of the adjustable flame fondue burner, the broken lines showing portions of a fondue pot that form no part of the claimed design.
The broken lines showing portions of the article and environment form no part of the claimed design.