Step 1

Preheat oven to 400 degrees F, and line a baking sheet with foil. Wash and dry the sweet potatoes and prick each one a few times with a fork.

Step 2

Place sweet potatoes on baking sheet and bake for 1 hour, flipping them at the halfway point, or until a knife slides in easily. Let cool for about 20 minutes or until cool enough to handle. Alternatively, sweet potatoes can be baked 1 to 2 days in advance and refrigerated until ready to peel and proceed with the recipe.

Step 3

Preheat a saute pan over medium-low heat. Toast pecans in the pan, stirring occasionally, for about 5 minutes or until fragrant. Transfer pecans to a plate to cool, then chop and set aside.

Step 4

Return saute pan to the burner and increase heat to medium. Cook the onion for about 5 minutes or until translucent, stirring occasionally. Add broth and garlic to the pan, and cook 3 to 4 minutes. Add rosemary, sage, and pepper, and cook until most of the broth has evaporated and onions are softened. Remove from heat.

Step 5

Peel the sweet potatoes, discarding the skins, and place in a large bowl. (If potatoes were made in advance and are still cool, warm them in the microwave or on the stovetop.) Add about ½ cup yogurt to the bowl, and use a potato masher or fork to mash the sweet potatoes. Add onion mixture and salt, and stir to combine. Taste and add more yogurt, salt, and pepper, as desired.

Step 6

Transfer mashed sweet potatoes to a serving dish. Garnish with a swirl of yogurt and chopped pecans.