In a large mixing bowl, whisk together flour, baking powder, salt, and sugar until well combined.

Chop butter into small cubes (about 30 pieces, or so). Scatter into the mixing bowl and cut into the flour mixture until the mixture resembles sandy crumbs. -- You can use two knives, a pastry cutter, or a hand-held electric mixer on low speed to cut the butter in.

In a separate bowl, lightly beat eggs with a whisk. Add buttermilk and vanilla; whisk until well combined. Stir in blueberries.

Add buttermilk mixture to the flour mixture. Quickly stir together by hand until mixtures are just combined (there may still be some lumps, and that's okay).

Immediately pour batter into a greased 9x5-inch loaf pan and place in a preheated 350℉ oven.

Bake for 60-65 minutes until a wooden pick inserted in the center comes out clean.

Cool in the pan for about 10 minutes. Then remove from pan to cool completely.

Store at room temperature for up to 1 day, or in the refrigerator for up to 5 days.

I use a hand-held mixer on low speed to cut the butter into the flour mixture, and it works super easy! With this method, you just need to keep the mixer speed on low and stop as soon as the mixture resembles sandy crumbs. -- We're going for crumbs here, not a dough or batter.

If you're finishing up this bread within about a day or so, it's fine to store it at room temperature. If it'll be enjoyed for longer than that, store it in the refrigerator. -- The blueberries in the bread are a bit "fragile" and do best refrigerated.