There are many reasons why you may need dark molasses substitutes, ranging from health reasons to a desire for a different kind of sweetness.
Dark molasses is a rich, thick, and very sweet syrup that is the byproduct of sugarcane. It most commonly pops up in traditional baking recipes for cookies, cakes, pies, and bread. It has a distinctive caramel and malty flavor, but there are some good alternatives out there if dark molasses isn’t in your pantry. 
Dark Molasses Substitutes
Being familiar with dark molasses substitutes can help keep your recipes under control, even if you are lacking this uniquely sweet ingredient. The best dark molasses substitutes include treacle, dark corn syrup, brown sugar, coconut palm sugar, maple syrup, honey, granulated white sugar, applesauce, and brown rice syrup among others.
Treacle is actually the same thing as molasses, but this is the British name! So, if you’re visiting Europe and are confused about the lack of dark molasses, try asking for treacle instead and you’ll basically end up with the same product.
Dark Corn Syrup
This syrup is an excellent alternative to molasses. It is similar in consistency and has a deep, rich flavor.
A flavorful and easily found alternative to molasses, brown sugar can be mixed with just a bit of hot water to make a thick sweet paste. To use brown sugar as a substitute for molasses, you will need 3/4 of the amount that is recommended for molasses. 
Coconut Palm Sugar
An unrefined sugar packed with minerals and flavor, coconut palm sugar makes a great and healthy alternative to molasses. Like brown or white sugar, mix it with a little hot water to use in baking recipes.
Although slightly thinner than molasses, maple syrup is just as sweet and can be used to substitute for dark molasses at a 1:1 ratio. 
A dark honey can be a decent substitute for dark molasses in certain recipes. The flavor of honey tends to be milder than molasses. The stronger, darker honey have their own distinctive taste, so be sure to consider that when planning for the overall taste of your dessert.
Granulated White Sugar
In a tight situation, you can substitute granulated white sugar for molasses in the same way as brown sugar (see above). This will give you the sweetness of molasses, but none of the spicy and rich flavors. Try adding a little cinnamon or vanilla essence to the paste to deepen the flavor.
Brown Rice Syrup
This amber syrup is a byproduct of rice. It has a deep and complex flavor that is quite similar to dark molasses, although it is thinner and less sweet. 
This is a very healthy option as a substitute! Applesauce has a different flavor but is both sweet and rich, so it can work in a number of sauces and some baking recipes.