Peel and slice the bananas into 1/4-inch-thick rounds. Have nearby a sheet pan lined with wax paper.
Place peanut butter into a microwave-safe bowl. Melt in the microwave for 15-20 seconds or just until it's easily spreadable. (It doesn't have to be hot)
Sandwich together two slices of banana with 1/2 teaspoon of peanut butter. Arrange on sheet pan. Repeat with the remaining slices. Freeze for at least 1 hour or until firm.
Place chocolate chips into a medium size microwave safe bowl with vegetable shortening or vegetable oil. Microwave on 50% power or using the melt function for 1 minute. Stir and continue to microwave in 30 second intervals until melted and completely smooth.
Using a fork, dip banana sandwiches into the melted chocolate covering completely on all sides, allowing excess chocolate to drip off.
Return to the prepared baking sheet. Sprinkle the tops with chopped peanuts while the chocolate is wet.
Freeze for 30 minutes or until chocolate is set.
Transfer to a freezer-safe container to store for up to 2 months.
Notes
Bananas - Choose bananas that are ripe but still firm. Overly ripe bananas that are soft won't work well here.
Peanut Butter - You can use Jif, Skippy, Peter Pan or a private store brand of peanut butter that you already enjoy.
Chocolate - You can dip these banana bites in melted white chocolate chips, milk chocolate chips or dark chocolate chips.
Vegetable Shortening - You can use coconut oil to thin the chocolate in place of vegetable shortening. Use unrefined coconut oil to avoid the coconut taste.
Alternate Nut Butters - You could make these banana sandwiches using almond butter, cashew butter or sunflower seed butter.
Reheat the Chocolate as Needed - If the chocolate gets firm while dipping, place it back into the microwave to reheat and thin. The cold bananas will naturally cool it down. If you're using a double boiler, you can remove it from the stovetop but keep the bowl over the hot water to keep the chocolate warm while you work.