Combine raspberries, sugar and lemon juice in a medium saucepan over medium heat. Cook, stirring, until sugar dissolves. Reduce heat to medium-low and cook, stirring occasionally, until raspberries begin to break down and release their juices, about 5 minutes. Transfer to a bowl and let cool completely. (Compote may be prepared up to 1 day in advance. Cover and refrigerate until use).
Lightly oil a 9 x 5-inch loaf pan with vegetable oil. Line bottom and sides with plastic wrap, leaving a 3-inch overhang on all sides.
Crumble meringues, leaving some large chunks. Arrange a 1/2-inch layer of crumbled meringues on bottom of prepared pan.
Beat cream on high speed in the bowl of an electric mixer until traces of the whisk appear. Add sugar and vanilla and continue to beat until soft peaks form. Fold in remaining meringues crumbles. Pour into prepared pan and smooth top. Cover with overhanging plastic. Cover pan with an additional piece of plastic to seal thoroughly. Freeze at least 8 hours or up to 24 hours.
To serve, remove pan from freezer and let stand at room temperature 5 minutes. Gently pull plastic to remove cream from pan. Invert onto a serving plate. Cut in 3/4-inch-thick slices. Serve with raspberry compote spooned over.