Directions

• Preheat oven to 375°F. Lightly coat a 12-cup muffin tray with cooking spray; set aside. Whisk together yogurt, honey, oil, vanilla, 1/2 cup sugar, 6 tablespoons melted butter, and 2 teaspoons orange zest in a large bowl. Add eggs, 1 at a time, whisking until smooth after each addition.
• Sift together flour, baking powder, salt, baking soda, and nutmeg in a medium bowl. Add about half of flour mixture to the yogurt mixture in large bowl, and fold with a rubber spatula until almost incorporated. Repeat process with remaining flour mixture, folding until just combined.
• Scoop batter into prepared muffin tray, about 1/3 cup per well. Bake until muffins are golden brown and a wooden pick inserted into center of muffins comes out clean, 22 to 25 minutes. Let muffins cool in tray on a wire rack until just cool enough to handle, about 5 minutes.
• Place remaining 1/2 cup melted butter in a medium bowl. Place remaining 1 cup sugar and remaining 1/2 teaspoon orange zest in a second medium bowl; rub mixture together with your fingertips to infuse the sugar with the orange oils. Working with 1 muffin at a time, roll muffin first in melted butter and then in the sugar mixture. Place on wire rack, and repeat process with remaining muffins.
• Using a paring knife or a 1/2-inch round piping tip, cut a 1/2-inch-wide by 1 1/2-inch-deep hole in center of each muffin top. Place jam in a large piping bag fitted with a 1/2-inch round tip or a ziplock plastic bag with 1/2-inch hole cut in the corner. Working with 1 muffin at a time, insert piping tip into hole, and fill with 2 to 3 teaspoons jam. Repeat with remaining muffins and jam. Serve muffins warm or at room temperature.