This was a great raspberry streusel but as I was making the recipe I decided the butter content was unnecessarily high compared to other streusels I’ve made. I cut out the extra 2 Tbs. butter from the topping. I think another 2 Tbs. could be omitted from the crust as well without any noticeable difference. My changes in green.
Source: Cook’s Illustrated
2 1/2 cups (12 1/2 oz) unbleached all-purpose flour
2/3 cup (4 3/4 oz) granulated sugar
1/2 tsp. table salt
16 Tbs. (2 sticks) plus 2 tablespoons unsalted butter, cut into 1/2-inch pieces and softened to cool room temperature (extra 2 Tbs omitted)
1 /4 cup (1 3/4 oz) packed light or dark brown sugar
1/2 cup (1 1/2 oz) old-fashioned rolled oats
1/2 cup (2 oz) pecans, chopped fine
3/4 cup (8 1/2 oz) raspberry preserves
3/4 cup (3 1/2 oz) fresh raspberries (frozen defrosted raspberries could be substituted)
1 Tbs juice from lemon (add only 1-2 tsp. if your raspberries are very tart)
1. Adjust the oven rack to middle position; heat oven to 375 degrees. Cut 18 inch length foil and fold lengthwise to 8 inch width. Fit foil into length of 13 by 9 inch baking dish, pushing it into corners and up sides of pan; allow excess to overhang pan edges. Cut 14-inch length foil and fit into width of baking pan in same manner, perpendicular to first sheet. (if using extra-wide foil, fold second sheet lengthwise to 12 inch width.) Spray foil-lined pan with nonstick cooking spray.
2. In bowl of standing mixer fitted with flat beater, mix flour, granulated sugar, and salt at low speed until combined, about 5 seconds. With machine on low, add 16 Tbs. butter 1 piece at a time, then continue mixing on low until mixture resembles damp sand, 1 to 1.2 minutes. (If using food processor, process flour, granulated sugar, and salt until combined, about 5 seconds. Scatter 16 tablespoons butter pieces over flour mixture and pulse until mixture resembles damp sand, about 20 1-second pulses.)
3. Measure 1 1/4 cups flour mixture into medium bowl and set aside; distribute remaining flour mixture evenly in bottom of prepared baking pan. Using hands or flat-bottomed measuring cup, firmly press mixture into even layer to form bottom crust. Bake until edges begin to brown, 14 to 18 minutes.
4. While crust is baking, add brown sugar, oats and nuts to reserved flour mixture; toss to combine. Work in remaining 2 Tbs. butter by rubbing mixture between fingers until butter is fully incorporated. (I omitted the extra 2 Tbs. butter.) Pinch mixture with fingers to create hazelnut-sized clumps, set streusel aside. (I make the clumps as I spread the topping over the streusel in Step 6.)
5. Combine preservers, raspberries, and lemon juice in a small bowl; mash with fork until combined but some berry pieces remain.
6. Spread filling evenly over hot crust; sprinkle streusel topping evenly over filling (do not press streusel into filling). Return pan to oven and bank until topping is deep golden brown and filling is bubbling, 22 to 25 minutes. Cool to room temperature on wire rack, 1 to 2 hours; remove from baking pan by lifting foil extensions. Using a chef’s knife, cut into squares and serve. Personally, I love it served warm!