Put biscoff cookies into a ziplock bag, then crush with the back of a measuring cup or a wooden spoon or meat mallet, until you have small chunks and crumbs. (Up to you how fine you want the crumbs to be.)
Put heavy cream into a mixing bowl, and use a hand mixer to whip for 20 seconds or so, until it starts to thicken. Then, continue to whip as you slowly pour in the sugar. Whip cream until soft peaks form.
Use a spatula to loosen up the cold mascarpone cheese, then add it bit by bit to the mixing bowl with the mixer on medium-low speed. Whip just until mascarpone is fully combined. Mixture should be thick and creamy.
Assemble parfaits by layering first a couple of spoonfuls of biscoff crumbs, followed by a couple of spoonfuls of the mascarpone mixture, followed by a sprinkling of strawberry pieces. You really don’t need to measure out exactly, just roughly eyeball the amount of the ingredients you have and make sure you have enough for 2 layers in each serving dish or glass.
Repeat with the second layer, ending with strawberries.
Serve immediately.
Notes
Don't over whip the heavy cream or the mascarpone. If you whip it for too long, you'll get a heavier consistency almost like whipped butter. It will still taste good but it won't be as light and fluffy to eat!It may seem like a good idea to soften the mascarpone before using by leaving it out at room temperature. Don't do this—mascarpone splits very easily when it warms up a little. Just use a sturdy spatula to loosen it a bit before adding to the bowl with the whipped cream. If your strawberries are super sweet, you can reduce the sugar a bit in the mascarpone layer. Use a clear glass or clear plastic dish to serve so that you can see all the layers. Smaller glasses are better than bigger since the mascarpone cream is quite rich, and a more narrow glass will make it easier to see the beautiful layers.