When frying bacon, it tends to curl up. I don't like it because my bacon doesn't cook equally and it's hard to get it crisp that way.
Is there a technique or a tip so I can have flat bacon?
This is how I cook bacon, and also produce almost perfectly flat bacon. No special tools required (Well, I'm assuming most people have the following in their kitchen).
The cooling rack should keep it from curling while the fat slowly renders out. As a bonus, I don't need to clean my stove after.
Alternatively, the mention of the George Forman grill reminds me of an idea I saw somewhere (might have been Good Eats), use a waffle Iron! Use it just like the grill in Ward's answer.
This is specifically the reason for the invention of Bacon Presses
This is the way I cook bacon and it almost always gives me flat bacon:
Put the bacon in a cold pan. Put the pan on the stove and turn it to medium heat. Let the fat slowly render out and fry the bacon on its own. Cook to your desired crispness
The gradual heating helps the bacon maintain its shape and is the best way to cook bacon, IMO.
This is very old practical way to get flat bacon - take your cold water bottle from the fridge, pour into a dish or pan, and let the strips of bacon lay in the coolness. In just a few minutes, the cool water will work its magic. Then cook. It will come out flat every single time. This is an old trick from my great grandmother. Don't dirty up a bunch of pans, or buy weights. Just use cold, cold water!
I made my own bacon press hack and it worked absolutely perfectly. First you need really decent bacon as there are some brands that have killer qualities, but most brands are lackluster, especially supermarket brands. One of these brands is Farmers applewood smoked that I get at Costco. It's a bargain but what is most important is that it tastes as good or better than most restaurants. I also freeze it in six slice sections because it freezes very well with no difference in taste from fresh because of it's high fat content.
That said, this bacon tends to curl. One thing I realized in my decades of bacon experience is that the bacon, and most food for that matter, tastes much much better when cooked under medium to high heat and in regards to bacon, it lends a beautiful crispy outside and a gentle chewy inside. Perfect texture!
Bacon press hack: I found a 5 quart pot that had a footprint that fit perfectly into my nonstick frying pan. Filled it with a few inches of water so it had some weight, and of course cleaned off the bottom really well, and tried this as a bacon press hack for the first time yesterday. All I can say is the result was perfect, even, bacon HEAVEN 🥓 . In lieu of a dedicated bacon press, this hack works perfectly.
If you are specifically frying them in a pan, I would turn the heat way down, and use a bit more oil. This cooks like it slowly, so the bacon doesn't curl. It does however take like, a good 30 mins to cook a strip of bacon. But you get nice orange color bacon that is ultra crispy.
Cutting the strip in half makes it curl less too.
Heat the oven to 400 degrees. Line a baking sheet with sides with parchment paper. Add the bacon, add a second pan to weigh it down. No need to turn
Second method: Place bacon in a cold skillet. Add another heavy frying pan over the top. Fry on low heat, turn after 5 to 8 minutes, turn with tongs, replace the other skillet, and fry until desired doneness: Chewy or crispy. No need for a press if using another skillet nested into the frying pan.
If I am pan frying, I cover the bacon with cold water, and cook on medium til the water evaporates. Then cook until finished. The bacon cooks evenly and stays flat. Since I like my bacon extra crisp I will put foil on the bottom of a small pot and press down on the bacon and let it sit for 1 minute or so depending on the cut of bacon.