The ideal time to deep fry frozen French fries is generally between 2 to 5 minutes at an oil temperature of around 350 to 375°F (175 to 190°C). Most sources agree that you fry the fries directly from frozen without thawing, and cooking them in small batches helps maintain oil temperature for crispy fries. Summary of key points:

• Heat oil to 350-375°F.
• Fry frozen fries for about 2-5 minutes until golden and crispy.
• Do not thaw the fries before frying.
• Cook in small batches to avoid oil temperature drop.
• French fries usually need just one fry since they are typically par-cooked before freezing.

For example, frying at 350°F generally takes about 3-4 minutes for thick-cut fries and about 2-3 minutes for thinner fries. This method achieves a crispy exterior and fluffy interior without excess oil absorption.

This deep-frying approach is commonly used in restaurants and recommended for best texture and flavor at home.