For the coffee cake batter:

1. Preheat your oven to 350 degrees. In a large mixing bowl, whisk together the butter, Greek yogurt, milk and eggs until smooth. Whisk in the sugar and vanilla.
2. Add in the 2 cups of flour, baking powder and salt and gently fold into the wet ingredients until a batter has formed. Being careful to not over-mix as this can cause the cake to dense. In a small bowl, toss the blueberries with the remaining 1 tablespoon of flour until coated.
3. Gently fold the blueberries and lemon zest into the batter. Carefully pour or scoop the batter into a greased angel food cake pan and even out the top.

For the crumble topping:

1. In a small bowl, mix together the melted butter, sugar, flour and almond extract until a crumble forms.
2. Evenly top the prepared coffee cake with the crumble topping. Bake for 50-55 minutes, or until just starting to turn golden brown on top and a toothpick inserted into the middle comes out clean.
3. Allow the coffee cake to cool in the pan for about 5-10 minutes before running a butter knife along the edges to loosen it to turn out. Turn the coffee cake out onto a baking sheet pan, then place the desired serving platter/plate onto the cake and carefully flip it back over to have it right side up. Some of the crumble topping may come off during this process but that is ok!
4. Serve warmed or allow to cool completely prior to covering and storing.