Preheat oven to 350 F.
Lubricate the inside of a Bundt cake pan with baking spray.
For about 3 minutes, cream the butter and brown sugar together in the bowl of a stand mixer with paddle attachment fitted (or in a large bowl using a hand mixer).
Just one at a time, add vanilla extract and eggs, scraping down the sides between additions.
By whisking, combine pastry flour, baking powder, baking soda, and salt in a separate bowl.
Add half of the flour mixture to the butter and sugar that was prepared, then mix until flour is completely fused together. Add Greek yoghurt and mix to combine. Then add remaining flour, scraping down sides after adding.
Pour mixture into prepared Bundt cake pan, then gently smooth the top with the back of a spatula.
Bake for 35 minutes, or until you see that the cake is golden brown on the outside and springs back a little when you try to push on it.
Rest and let cool in pan for at least 15 minutes, then overturn onto a wire rack to cool completely before adding glaze.
Combine all needed ingredients for the glaze in a small bowl, then whisk until you have a smooth consistency. Add water at about 1 teaspoon at a time, and whisk until desired thickness is attained.
Drizzle on top of cooled cake.