Here’s a fast, methodical way to dice a bell pepper. First, cut off the top end. (Once you’re done dicing the full pepper, you can slice off the edges of the top to use.)
Next cut off the bottom. Save it to slice or dice, too.
Split the pepper from top to bottom with a single cut.
Pull out the pepper’s core, and discard it.
Now just unfold the pepper like a book. Some peppers will break apart here, which is fine.
Cut the pepper into sections along the white bitter ribs, which you’ll want to remove. This way they’re easier to get at with a knife.
Hold the knife parallel to the cutting board and cut between the ribs and the red flesh below.
Now you’re left with relatively flat sectioned pieces of bell pepper. Slice them into thick or thin strips, depending on the size dice you want.
To complete the dice, rotate the strips 90 degrees and slice them crosswise.