Need recipes with a long prep / cook time?

Cheese ravioli

I just thought of one more which doesn't take all day but I wouldn't do it when I come home from work. Roasted red pepper sauce. The flavor if incredible. You can freeze is nd use it as sauce later or thin it with chicken stock for soup. I use the America's Test method of roaring the peppers. Cut out the stem in a round, cut down the side and flatter. Seed the pepper. Run under the broiler until blackened. Steam the in a bag & Skin the peppers. Sautee onions and garlic in olive oil. Cool. Put in all in the cuisinart. Freeze in freezer bags. My favorite is to serve it on. Geese ravioli.

I've done this and share with friends and family. I bake many different varieties of cookies. Make up plates and give the away. They are well received and you cam get as fancy as you want....bar cookies, shortbread, drop, truffles, chocolate bark, mix it up. What a wonderful accomplishment and you make people happy! :)

I'd add cheesemaking to this list. Can require some constant presence/work (stirring to prevent scorching, etc) and it feels like alchemy and magic!!!

When I am able to spend a decent amount of time in the kitchen I like to make preserves. The other project I have in mind is making a timpano. There is a recipe on this site, but other videos on youtube that I watch to prepare for the time I will eventually take to make this dish. Stanley Tucci also has a recipe I have looked at. I probably won't make the pasta that goes inside the timpano, but I will make the dough that surrounds and becomes the crust for the dish.

I'd probably want to master some techniques, but also make those items that have always seemed so intimidating. I'd want to learn to make a variety of Asian dumplings (and stock my freezer) and pierogi. Second on the cabbage rolls, and tamales too. Pretzels and crackers...I never seem to have the time to make those. I'd also like to master puff pastry (which also freezes well) and some of the French, Danish, and Austro-Hungarian pastries made from that dough. Macaron of course. And I want to learn how to use all the different attachments of my cookie press and the piping bag and tips.
Let us know what you decide to do! Maybe keep a log of what techniques you've learned and mastered, to guide us.
Hope all goes well with your time off.

As someone who's currently babysitting a pot of pork stock, I would recommend making and freezing (or canning if you have a pressure canner and limited freezer space) all kinds of stocks and reductions. I know there's lots of great shortcuts for making a quick stock for soup or stew that night, but I've found that having old school, long cooked stocks in the fridge makes everything that little bit richer and deeper in flavor. And its the only way to go for the demi glace mentioned above. If you're interested, the most comprehensive stock technique is described in Sauces: Classical and Contemporary Sauce Making by James Peterson, absolutely worth looking for in your library.

Tap some maple trees and make syrup before it gets too warm.

You could try canning. It's not exactly that time of year. But, if you have access to decent tomatoes and peppers you can make and can sauce and salsa. We were really intimidated at first but it's not hard. You could also make jam. Strawberries come to mind. Last year we made refrigerator pickles. We are thinking about trying jardiniere next. You can also brine and smoke meat or try out your own sausage. Demi glacé takes lots of time. Right now we are trying Shanghai soup dumplings (see Serious Eats) which is very challenging. Have fun and good luck!!

I'd take the time to do a full organization of my freezer and recipe/weeknight meal strategies, and then develop and implement a workable, longterm system involving regular batch cooking, freezing and then putting components to use, from the freezer, for when you go back to work. I have many ideas and suggestions on this, plus resources that I've developed as I've mentored several young professional women on how to make this work. I've chimed in on this many times in other Hotline threads and comments to posts here. Please let me know if you're interested in more details. ;o)

I'd make cabbage rolls. I love them and never make them because of the time it takes.

As others have suggested, bread esp recipes by j child for french, bernard clayton & james beard for basic technique and reliable recipes.
Also restaurant based cookbooks for home cooks. Often maddening in a regular week with multiple day productions & sub recipes, but ideal to tackle while on leave. Pick a cuisine or chef you like. One example: French Laundry cookbook.

Bread baking for sure. If you have the kitchen equipment, fiddly pastry recipes maybe? Macaron are also fun but not super fast - I usually take a weekend to make mine, between various fillings, aging egg whites, etc. Oh also home made ramen! I'm talking whole 9 yards of home made 24-48h broth, braised meets, marinated eggs. I made it once, was amazing, and won't do it again while I'm employed - try tonkotsu ramen broth from serious eats.

I suggest you get a Julia Child cookbook and work through some classics. This will consume large amounts of time in my limited experience.

I like making pasta. It's cheap being mostly flour and you can mix and shape it with no equipment whatsoever. It's also delicious. If you really want to get ambitious make filled things like ravioli, pierogi, and chinese dumplings. All these can go in the freezer to make nights you don't want to cook a cinch.

I do tend to make mine using the food processor. Here's my recipe: http://www.justapinch.com/recipes/main-course/italian/fresh-pasta-in-the-food-processor.html. To see lots of videos showing pastas you can shape by hand, go to youtube.com and search 'shaping pasta by hand.'

You could try getting into bread baking... I've recently jumped on the sourdough bandwagon, and I can promise that it is time consuming and challenging (but very delicious). If you start your starter now, it should be ready for your break. Also, dishes that take a long time to prepare - if everything is prepared individually - that I love are enchiladas (preparing the tortillas from scratch (even with sourdough starter!), preparing the sauce from scratch, roasting veggies, etc...), dumplings, and homemade pasta.