Copycat Dairy Queen Ice Cream Cake

1. Stage

Preheat oven to 350° and line a baking sheet with parchment. Using a sharp knife, chop Oreos into chickpea-sized pieces. Transfer to a medium heatproof bowl and toss with butter. Spread onto prepared sheet and bake until fragrant and crisp, 5 to 8 minutes.

2. Stage

Meanwhile, wipe out bowl. In same bowl, microwave chips in 30-second increments, stirring between each, until melted and smooth, 60 to 90 seconds total. Stir in oil.

3. Stage

Add cookie crumbs to chocolate mixture and toss to coat. Spread on another parchment-lined sheet and refrigerate until hardened, about 30 minutes. Chop into small pieces.

4. Stage

Make Ahead: Chocolate cookie crunchies can be 1 day ahead. Store in an airtight container and refrigerate.

5. Stage

Line a 9" springform pan with plastic wrap. In a large bowl, stir vanilla ice cream until smooth and spreadable (but not liquid). Using an offset spatula, evenly spread in bottom of prepared pan. Freeze 30 minutes.

6. Stage

Meanwhile, uncover jar of fudge topping and microwave in 15-second increments, stirring between each, until slightly warmed and spreadable, 30 to 45 seconds total.

7. Stage

Scatter chocolate crunchies on top of frozen ice cream. Dollop fudge across crunchies, then carefully spread with an offset spatula. Freeze cake until slightly firm, 15 to 30 minutes. 

8. Stage

In a large bowl, stir chocolate ice cream until smooth and spreadable (but not liquid). Carefully spoon over fudge layer and gently spread until smooth. Cover top of cake and freeze until firm, at least 4 hours or up to 1 week.

9. Stage

About 2 hours before serving, peel off top plastic wrap layer, leaving chocolate ice cream exposed. Invert cake onto a platter, with chocolate layer at the bottom. Remove sides of springform pan and peel off remaining plastic wrap. Return to freezer while whipping cream.

10. Stage

In a large bowl, using a handheld mixer on medium high-speed, beat cream, confectioners' sugar, and vanilla until stiff peaks form. Transfer about one-third of whipped cream to a piping bag fitted with a star tip.

11. Stage

Spread remaining whipped cream over top and sides of cake. Pipe a shell border around top edge and base of ice cream cake, if desired. (If cake starts to melt, return to freezer until firm and refrigerate whipped cream.)

12. Stage

Freeze decorated cake, uncovered, 1 to 2 hours before serving.

13. Stage

Just before serving, sprinkle top edge and base of cake with sprinkles. Let sit at room temperature about 5 minutes, then cut into slices with a sharp knife.