In a stand mixer, whip cream to soft peaks. Add in sugar and salt and mix until well combined. Add in the mascarpone and whip until full incorporated. With the mixer still running, add in 1/4 cup Baileys. Set aside.
In a shallow dish, mix together coffee and 1/2 cup Baileys. One by one, dip the lady fingers into the mixture and place an even layer of them into the bottom of a 3-quart dish. Once you've completed a layer, top the lady fingers with half of the whipped cream mixture. Repeat, making one more layer of soaked lady fingers and one final layer of cream. Cover the dish with plastic wrap and place into the fridge for at least 2 hours, or overnight.
When you're ready to serve, dust the top with cocoa powder.