In a bowl, combine the spices and lemon juice, and give it a good mix.
Add the paneer cubes and pepper and mix with the spice blend, then let the mix hang out in the fridge for 30 minutes.
Melt the butter in a big saucepan over medium heat.
Add the chopped onion and cook for 5 minutes, until soft.
Add in the minced garlic and let it cook for another 2 minutes.
Add in the marinated paneer and pepper, then cook it all together for 5 minutes. Stir it occasionally to make sure it cooks evenly.
Now add in the tomato paste and heavy cream. Give it a good stir, then let it simmer for 5 minutes.
Top it off with some chopped fresh cilantro or parsley before serving.