Preheat the oven to 375°F and grease the doughnut pan.

In a medium bowl, whisk together flour, cinnamon, nutmeg, baking powder, and baking soda.

In a separate large bowl, cream softened butter and brown sugar until light and fluffy.

Add egg and vanilla extract to the creamed mixture and beat well.

Mix in yogurt, crushed pineapple, and shredded carrots.

Gradually add dry ingredients to the wet mixture, mixing until just combined.

Spoon batter into the prepared doughnut pan, filling each cavity 1/2 full.

Bake for 10 minutes or until a toothpick inserted comes out clean.

Allow doughnuts to cool in the pan for 5 minutes, then transfer to a wire rack.

Meanwhile, beat together cream cheese, pineapple juice, and orange juice. Mix in powdered sugar and orange zest to make the glaze.

Dip cooled doughnuts into the glaze and top with toasted walnuts.