Preheat oven to 375°F.
In a small bowl, combine flour, baking soda, and salt, whisking to combine thoroughly.
In a small food processor (we use the smallest container in our Ninja set), combine chickpeas, oil, and butter. Process until smooth, scraping bottom and sides as necessary to make sure no chunky bits remain.
Transfer buttery chickpea mixture to a large bowl. Add sugar, peppermint, and vanilla. Use a hand mixer to beat until smooth. Add eggs one at a time, beating after each addition. Then, gradually beat in flour mixture in three or four additions. Beat just until thoroughly combined.
Stir in white chocolate chips.
Press the dough into a 9x9 baking pan (lightly coated with cooking spray, if needed – if using a stoneware baking pan like I did in the photos, you will not need to grease the pan). Smooth the top with a rubber scraper.
Bake until lightly golden brown (just slightly darker at the edges), and dry and puffed on top, about 18-23 minutes. (Different types of baking pans may require a slightly different bake time). Do not over-bake or your blondies will be dry.
Cool completely in pan, on a cooling rack, before cutting.
Make-ahead and freezing tips: If you'll be storing these blondies for more than a day or two, they'll stay fresher tightly sealed or covered with plastic in the refrigerator. These blondies also freeze well – wrap them tightly in plastic and store them in air-tight zipper bags.