Preheat oven to 350°F.
In a medium bowl, whisk together flour, sugar, baking powder, baking soda and sea salt.
In a small bowl, whisk together butter and egg until smooth. Add in yogurt, milk and vanilla and whisk until smooth.
Pour wet ingredients into dry and stir to combine. The dough will be a thick consistency but if it seems a bit dry, add a splash of milk. Try not to over stir as well.
Spray oil into donut baking pan to coat. Spoon donut batter into the molds or pour batter into a plastic bag and cut a slit to fill donut molds. I prefer this method and found it to be a lot less messy!
Bake for 9-10 minutes, until golden brown and a toothpick comes up clean. Remove from oven and allow to cool thoroughly.
While donuts cool, or before serving, whisk together glaze adding maple to desired thickness and dip each donut into glaze and set aside to dry--or dig in immediately!