Position the oven's top baking rack in the middle of the oven and preheat it to 350F. Grease a 9×13-inch baking dish.
Make the batter:
In a large bowl or the bowl of your stand mixer, combine the all-purpose flour, sugar, baking powder, and salt.
On top of the dry ingredients, pour the milk, add the Greek yogurt, softened butter, lemon zest, eggs, and vanilla. Mix on low speed until combined and there are no visible clumps. The batter will be thick. Add the blueberries into the batter and fold them in with a spatula.
Pour the batter into the greased baking dish.
The crumble topping:
In a small bowl, mix the flour and sugar. Then, add the chilled and cubed butter. Use your hands to mix it until it resembles a coarse, sand-like topping.
Sprinkle the crumble topping on top of the batter.
Bake:
Bake in the preheated oven for 50 to 60 minutes, until a toothpick inserted in the middle comes out clean.
Remove it from the oven and allow the coffee cake to cool down to room temperature before slicing.
Storage:
Cover leftover coffee cake with plastic wrap or inside a lidded container. On the counter, at room temperature for 2 days or in the refrigerator for up to 5 days. Freeze individual coffee cake pieces in zip bags or wrapped in plastic wrap for up to 2 months.