Speculaas/Biscoff cookie low calorie aroma extract
The taste of a Speculaas is a lot more complex than just the spices.

So if you want to recreate it without crumbling up a cookie, you need:


The spices:
Probably the most obvious part, but finding the "right" mix can be a challenge. Spices vary greatly between brands and recipes, both in ratios and intensity. Where a simple recipe might use cinnamon, cloves and cardamom, others pull all stopps and also include pepper, ginger, nutmeg and possibly others. And of course "right" in this case is a matter of personal taste.
The sugar:
Yes, you want to save calories, but a major contributor to the flavour profile is the sugar. You need the molasses in the brown sugar, and the caramel, that is created during baking. 
The butter:
Kind of obvious, but butter has its own characteristic flavour and yes, it is part of the speculaas taste. It may be easier to skip than other compounds, but when we are talking about mouthfeel and how the flavour develops when tasting a dish, it plays an important role. Many aromatic compounds are soluble in fat, not water.
The flour:
Part of the speculaas taste is what we percieve as "baked flavour" or "cookie" and apart from caramelization (which is covered to a greater extent by the sugar), we are also looking at the results of the Maillard reaction. 


So if you start "building" the flavour or "removing" unwanted sugar or fat calories, you will probably end up with a meagre immitation of what you love. 

Sometimes choosing the real thing and enjoying it in moderation can be more satisfying than feasting on a substitute, and in my personal opinion, this is one of these cases.