Cook bacon strips in a skillet over medium heat until crispy - 5 to 8 minutes. While bacon cooks, finely chop shallot and spinach.
Remove bacon from the pan and set on a paper towel lined plate to remove excess grease. Carefully remove all but about a tsp of bacon grease from your pan (do not dump it down your sink!). Once cooled, chop bacon into small bits and set aside.
Add shallot and spinach to pan, and cook until shallots are translucent, and spinach is just wilted, about 3 minutes. Set aside to cool for a few minutes.
In a small mixing bowl, add mascarpone, 2 tbsp parmesan cheese, lemon zest, spinach and shallot, and bacon bits. Stir to combine.