Preheat oven to 350°F (177°C). Spray donut pan with non-stick spray. Set aside.

Whisk the flour, baking powder, baking soda, cinnamon, nutmeg, cloves, and salt together in a large bowl. Set aside.

Whisk the melted butter, egg, brown sugar, milk, yogurt, and vanilla together until completely combined.

Pour the wet ingredients into the dry ingredients and whisk until just combined. Do not overmix.

Spoon the batter into the donut cavities using a large zipped-top bag, filling each donut cup about halfway.

Bake for 10-11 minutes or until the edges and tops are lightly browned. To check for doneness, gently poke a donut; if it bounces back, it's done.

Allow donuts to cool for a few minutes in the pan, then transfer to a wire rack set on a large piece of parchment paper.

In a small saucepan over low heat, melt the butter and maple syrup together, whisking occasionally.

Once the butter has melted, remove from heat and whisk in the sifted confectioners’ sugar and maple extract. Add a pinch of salt if desired.

Cool the icing for 2-3 minutes, then dip each donut into the icing. Place dipped donuts back onto cooling rack.

Serve immediately or store leftovers covered at room temperature or in the refrigerator for up to 2 days.