Whole Wheat Rhubarb Streusel Muffins
Cooking note: I had intended to replace the majority of the flour with white whole wheat flour. I realized when I was editing photos and saw the flour bag in the background of an image that I’d used whole wheat pastry flour instead! So, either will work. If you’re using standard whole wheat flour, for maximum tenderness I might go halvsies with the flour instead — 3/4 cup white, 3/4 cup whole wheat.
Streusel 1/4 cup (31 grams) all-purpose flour 1/4 cup (28 grams) white whole wheat flour 1 tablespoon (13 grams) granulated sugar 3 tablespoons (38 grams) light or dark brown sugar 1/4 teaspoon ground cinnamon Pinch of nutmeg Pinch of salt 3 tablespoons (42 grams) unsalted butter, melted
Muffin 1 large egg 1/4 cup (50 grams) light or dark brown sugar 3 tablespoons (38 grams) granulated sugar 5 tablespoons (71 grams) unsalted butter, melted and cooled to lukewarm 3/4 cup (177 ml) sour cream 1 cup (approx. 120 grams) white whole wheat flour or whole wheat pastry flour (see Note) 1/2 cup (63 grams) all-purpose flour 1 1/2 teaspoon baking powder 1/4 teaspoon baking soda 1/4 teaspoon salt 1 cup diced rhubarb, in 1/2-inch pieces (from about 6 to 8 ounces of stalks)
Preheat oven to 375°F. Butter 12 muffin cups.
Make streusel: In a small dish, stir together flours, sugars, spices and salt. Stir in butter until crumbly. Set aside.
Make muffins: Whisk egg in the bottom of a large bowl with both sugars. Whisk in butter, then sour cream. In a separate bowl, mix together flours, baking powder and baking soda and stir them into the sour cream mixture, mixing until just combined and still a bit lumpy. Fold in rhubarb and 1/3 (feel free to eyeball this) of the streusel mixture.
Divide batter among prepared muffin cups. Sprinkle each muffin with remaining streusel, then use a spoon to gently press the crumbs into the batter so that they adhere. Bake for 15 to 20 minutes, until tops are golden and a tester inserted into the center of muffins comes out clean. Rest muffins in pan on cooling rack for two minutes, then remove muffins from tin to cool them completely.