Hache Parmentier is pretty much the French version of shepherd's pie.

In the third episode of Ludo à la Maison, chef Ludo Lefebvre makes shepherd’s pie with a very special guest: his son, Luca.

While shepherd’s pie is a classic English dish, there’s a French equivalent: hache parmentier. “It tastes exactly the same,” Lefebvre says. “I don’t know who stole the recipe.” But since the chef is both French and British, as he found out by taking a 23andMe test (the company is sponsoring his show), he comes to the conclusion that “it doesn’t matter.”

Something else that doesn’t matter, in Lefebvre’s world anyway? The fact that Luca doesn’t chop vegetables perfectly—no matter how many times Lefebvre tries to teach him—because at the end of the day, the most important thing is how the dish tastes.

The key to achieving great flavor in this hearty meat and potato pie—whether it’s the British version or the French one—is executing the mashed potatoes correctly. And, of course, Lefebvre has two important tips:

First, Lefebvre recommends peeling the potatoes when they’re still warm, since it’s easier to separate flesh from skin that way. If you’re lucky, the skin will just slide right off.

But don’t peel those spuds into the trash—which is where his second tip comes in. Instead, save the skins and use them as part of the mashed potatoes. “I love to cook my potatoes with the skin,” Lefebvre says. “The skin protects the pulp of the potato from the water.”

When it comes time to focus on the meat part of the pie, Lefebvre deglazes the pot with white wine. But he also needs to reduce the wine in order to get rid of the remaining alcohol flavor. To do this, Lefebvre adds water to the mixture, allowing the minced meat to soak up all of the liquid.

Check out Lefebvre's full recipe here.