Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper and lightly spray it with cooking spray or brush it with oil.
In a mixing bowl, whisk together the flour, sugar, baking powder, baking soda, salt, and cinnamon until well combined.
In another bowl, mix the buttermilk, applesauce, egg, and vanilla extract until smooth.
Pour the wet ingredients into the bowl with the dry ingredients and gently mix until just combined. Be careful not to overmix.
Fold in the blueberries carefully to avoid breaking them apart.
Using a spoon or a small cookie scoop, drop spoonfuls of the batter onto the prepared baking sheet, leaving space between each fritter bite.
Bake in the preheated oven for about 15-20 minutes, or until the fritter bites are golden brown and a toothpick inserted into the center comes out clean.
Remove from the oven and let them cool on the baking sheet for 5 minutes. Then, transfer them to a cooling rack to cool completely.