You know what takes a lot of time? Standing over the stove and browning every cube of stew meat on all sides and in batches. That's why we brown the pork shoulder whole, which develops a ton of flavor...
This is a refreshing change from the baby food preparation that too frequently befalls the hapless squash. It makes an impressive dish when sliced into wedges and surrounded by roasted veggies.
Lots of Tex-Mex restaurants use bottled mole pastes from Mexico such as Doña Maria brand. Tricks of the trade include reconstituting the paste with chicken broth instead of water and boosting the flavor...
A well-seasoned cast-iron pan is your friend here. If, despite your best efforts, the frittata sticks when you turn it out, just flip it back over so that any imperfections are hidden underneath.