Preheat the oven to 425F.

Line a baking sheet with parchment paper (or use a small baking dish).

If using sweet potatoes, halve them lengthwise and place halves cut-side up on the prepared baking sheet.

Bake until they are fairly soft but not falling apart, about 30 minutes.

Remove from the oven and, protecting your hands, use a large spoon to hollow out the center of each half, creating a hole large enough to hold an egg. (Reserve the scooped sweet potato for another use.)

If using bell peppers or avocados, halve them lengthwise through the stem.

Remove stems and veins from pepper halves with a spoon or remove pit from avocados.

Enlarge center hole of each avocado half slightly so it is large enough to hold an egg.

Place "boats" on the prepared baking sheet; if needed, cut a sliver off bottom of bell pepper or avocado halves so they sit level.

Sprinkle sweet potato, bell pepper or avocado boats with 1/4 teaspoon of the salt.

Crack an egg into each and sprinkle top with pepper and remaining 1/4 teaspoon salt.

Bake 10 to 12 minutes for sweet potatoes and avocados and about 15 minutes for bell peppers, or until eggs are set and vessels are soft.