Preheat oven to 350°F. Line 2 baking sheets with parchment paper or silicone baking mats and set aside.

Lightly spoon 1 cup all-purpose flour into a dry measuring cup; level with a knife.

In a bowl, sift together the measured flour, 1/4 teaspoon baking soda, and 1/8 teaspoon salt; set this dry mixture aside.

In a large saucepan over medium heat, melt 5 tablespoons butter, stirring until fully melted.

Remove the saucepan from the heat and immediately stir in 7 tablespoons unsweetened cocoa, 2/3 cup granulated sugar, and 1/3 cup packed brown sugar until the mixture is evenly combined and resembles coarse sand.

Stir in 1/3 cup plain low-fat yogurt and 1 teaspoon vanilla extract until smooth and combined.

Add the sifted flour mixture to the cocoa mixture and stir just until the dough is moist and evenly blended.

Drop the dough by level tablespoons onto the prepared baking sheets, spacing cookies about 2 inches apart.

Bake in the preheated oven for 8 to 10 minutes, or until the cookies are almost set.

Remove the baking sheets from the oven and let the cookies cool on the pans for 2 to 3 minutes or until they are firm enough to transfer.

Transfer cookies to wire racks and cool completely.