Whisk sugar, cinnamon, salt, and butter in medium bowl to combine. Add flour and stir with rubber spatula or wooden spoon until mixture resembles thick, cohesive dough; set aside to cool to room temperature, 10-15 minutes.
Adjust oven racks to upper middle position and heat oven to 325 degrees F.
Cut 16" length of parchment paper or aluminum foil and fold lengthwise to 7" width. Spray 8" square baking dish with non-stick cooking spray and fit parchment into dish, pushing it into corners and up the sides; allow the excess to overhang the edges of the dish.
In the bowl, of a standing mixer fitted with the paddle attachment, mix flour, sugar, baking soda, and salt on low speed to combine. With mixer running at low speed, add butter one piece at a time; continue beating until mixture resembles moist crumbs, with no visible butter chunks remaining, 1-2 minutes. Add egg, egg yolk, vanilla extract, and buttermilk; beat on medium-high speed until light and fluffy, about 1 minute, scraping once if necessary.
Transfer batter to baking pan; using rubber spatula, spread batter into an even layer. Break apart the crumb topping into large, even-sized pieces and spread in an even layer over the batter, beginning with the edges and working toward the center.
Bake until crumbs are golden and a wooden skewer inserted into the center of the cake comes out clean, 35-40 minutes. Cool on a wire rack for at least 30 minutes.
Remove the cake from the pan by lifting the parchment overhang. Dust with confectioner's sugar just prior to serving.
View line-by-line Nutrition Insights™: Discover which ingredients contribute the calories/sodium/etc.
|Serving Size: 1 Serving (115g)|
|Recipe Makes: 8 Servings|
|Calories from Fat: 243 (49%)|
|Amt Per Serving||% DV|
|Total Fat 27g||36 %|
|Saturated Fat 16.8g||84 %|
|Monounsaturated Fat 7g|
|Polyunsanturated Fat 1.2g|
|Cholesterol 95.9mg||30 %|
|Sodium 64.6mg||2 %|
|Potassium 86mg||2 %|
|Total Carbohydrate 59.3g||17 %|
|Dietary Fiber 0.7g||3 %|
|Sugars, other 58.6g|
|Protein 4.4g||6 %|
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Disclaimer: Nutrition facts are derived from linked ingredients (shown at left in colored bullets) and may or may not be complete. Always consult a licensed nutritionist or doctor if you have a nutrition-related medical condition.
Calories per serving: 493
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