Slice about 1-inch off of the top of the cake and set aside.
Carefully hollow out the center portion of the cake, leaving the outer and inner walls, as well as about a 1-inch shell on the bottom.
Reserve cake pieces and tear into 1-inch cubes.
In a large bowl, beat the softened cream cheese until fluffy.
Add Eagle Brand and lemon juice, beating until smooth.
Stir in almond extract and food coloring until desired color level is reached.
Fold in 1 cup whipped topping, then carefully stir in reserved cake pieces and strawberries.
Spoon the strawberry mixture into the hollowed out cake; replace cake top.
Use remaining whipped topping to frost the rest of the cake.
Refrigerate for at least 3 hours or overnight.
If you have any strawberries left over, remove stems and add extra slices on top of the cake.
Architectural Differences from Standard Sponge Cakes
Standard layer cakes rely on alternating discs of crumb and frosting, but tunnel cakes utilize a hollowed-out cavity to contain heavy fillings. Angel food cake provides the ideal structural foam for this technique because its high proportion of whipped egg whites creates an open, spongy matrix capable of absorbing moisture without collapsing entirely. Leaving a 1-inch shell at the base and sides is critical; cutting too close to the exterior compromises the walls, causing the liquid from the fruit and dairy mixture to seep through to the serving platter.
Substitutions and Structural Integrity
Modifying the dairy components alters the viscosity of the filling significantly. Condensed milk provides dense sugars that bind free water, preventing the cream cheese mixture from weeping into the surrounding crumb. Swapping fresh strawberries for frozen fruit requires a preliminary thawing and thorough pressing step through a paper towel lined strainer to remove excess surface moisture. Introducing un-drained frozen fruit introduces excess water content, which dissolves the structural rigidity of the whipped topping folded into the batter.
Refrigeration and Holding Windows
Chilling the assembled dessert for a minimum of 3 hours allows the starches and dairy proteins to set fully, transforming a loose filling into a sliceable paste. Storing this dessert in a domestic refrigerator for up to 24 hours actually improves the overall texture, as the internal moisture equilibrates between the dense cream cheese core and the dry angel food exterior. Freezing is strongly discouraged because the high water content in thawed strawberries and whipped topping separates upon defrosting, yielding a watery emulsion that ruins the sponge.