For coffee cake: Mix cake mix, boxed cake mix ingredients and jam in the bowl of a stand mixer until evenly combined. Add in strawberries, stir together on LOW or mix by hand.
Pour batter into a sprayed 9" springform pan. Set on a rimmed baking sheet (to catch any leaks).
Stir together the flour and sugar. Using a food processor (or your fingers) cut the cold butter into the flour/sugar mix until coarse crumbs form. Squeeze together to create larger streusel pieces, the sprinkle evenly over the batter.
Bake according to box directions, watching for your end time- mine ended up around 50 minutes. You'll need to check occasionally until a toothpick comes out clean.
Remove to a wire rack to cool, then unclip the springform. Sprinkle with powdered sugar.