In a medium bowl, toss the strawberries, 1 tablespoon sugar and the lemon juice until the sugar dissolves. Let sit out at room temperature while you prep the remaining ingredients. Add the mascarpone to a large bowl. Beat with a hand-held mixer until soft and loose. Add the heavy cream, the remaining 1 tablespoon sugar and the vanilla and whip until you reach soft peaks.
Add a layer of crumbled biscotti to the bottom of two 12-ounce martini glasses (or any other decorative glass). Top with a layer of whipped mascarpone, and then a layer of strawberries. Repeat the layering. Sprinkle with the remaining crumbled biscotti.
You can make up to 3 hours ahead of time and store in the refrigerator, or serve right away.