Mix Dry Ingredients: In a large bowl, combine the flour, sugar, and salt.

Add Oils and Butter: Drizzle in the vegetable oil and mix until the flour is slightly moistened. Add the cool butter pieces and use a pastry cutter or your fingertips to work the butter into the flour until the mixture resembles coarse crumbs.

Form the Dough: Combine the cool water and vinegar (or lemon juice). Gradually add this to the flour mixture, stirring until the dough begins to come together. You may not need all the liquid.

Chill the Dough: Gather the dough into a ball, wrap it in plastic wrap, and chill for at least 1 hour.

Preheat Oven: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.

Prepare Filling: In a small bowl, mix the Greek yogurt, honey, lemon zest, and egg yolk until smooth.

Roll the Dough: On a lightly floured surface, roll out the chilled dough into a 12-inch circle. Transfer it to the prepared baking sheet.

Assemble the Galette: Spread the yogurt mixture evenly over the dough, leaving a 2-inch border around the edges. Pile the blueberries on top of the yogurt mixture.

Fold the Edges: Fold the edges of the dough up and over the filling, pleating as necessary. This rustic look is what makes a galette so charming!

Egg Wash: In a small bowl, beat the egg and water together. Brush the edges of the dough with the egg wash.

Bake: Bake for 35-40 minutes, or until the crust is golden and the blueberries are bubbling.

Finish with Honey: Drizzle a bit of extra honey over the top of the warm galette before serving.