This is one of several recipes I like, if the instructions look do-able for your event and not too fussy(?). Like a lot of bars, it does call for a 350 oven. They are kind of decadent!

Caramel Crumb Bars (Recipe from Nick Malgieri)

Dough
2 sticks butter, softened
1/2 cup sugar
1/4 tsp salt
1 tsp vanilla extract
2 1/2 cups all-purpose flour

Filling
4 T butter
1 T light corn syrup
1/4 cup dark brown sugar, firmly packed
1 (14 oz) can sweetened, condensed milk

One 9 x 13 x 2 inch pan, buttered and lined fully (bottom and sides) with buttered parchment or foil

Set rack in lowest level of oven and preheat to 350.

For the dough, beat the butter, sugar and salt in an electric mixer with the paddle attachment on medium speed until soft and light, 2-3 minutes. Add the vanilla.

On lowest speed, beat in 2 1/4 cups flour, scraping the bowl and paddle with a rubber spatula, continuing to mix until the dough is smooth, and the flour has been absorbed.

Remove the bowl from the mixer and scrape 3/4 of the dough into the prepared pan. Using your palm, press the dough down evenly, without compressing it too much. Chill the dough lined pan. Work the remaining 1/4 cup flour into the remaining dough with your fingertips, so that it forms 1/8-1/4 inch crumbs. Set aside at room temp.

For the filling, in a medium saucepan, combine all filling ingredients and simmer, stirring occasionally. Allow the mixture to boil gently, stirring often, until it starts to thicken and darken slightly, about 10 minutes. Pour into a stainless steel bowl to cool for 5 minutes.

Remove the dough lined pan from the refrigerator and scrape the cooled filling onto the dough, using a small offset spatula to spread the filling evenly on the dough. Scatter the crumb mixture on the filling.

Bake until the filling is bubbling gently and is a deep caramel color and the dough and crumb topping are baked through, about 30 minutes.

Cool in the pan on a rack until lukewarm. Lift the slab of baked dough out of the pan and onto a cutting board before it has cooled completely. Cut the slab into 2 inch squares.

These are some I made for a Halloween gathering several years ago.

I'll stick to fudge brownies as I previously suggested.

Cranberry curd bars are also awesome but I'm dreaming of a cross between cranberry curd and a rich, shattery rather than sticky, hazelnut toffee.

If you have a favorite drop cookie recipe, most can be made into bars, too. The dough can be pressed into a pan 3/4“ to 1” thick, and the baking time will increase maybe twice as long as for cookies. No higher than 350 and just keep an eye on them.

Lemon bars always seem welcome. I sometimes add a layer of raspberry jam on top of the crust before adding the lemon filling.

Speaking of raspberries, Cook’s Illustrated has a very good recipe for Raspberry Oat Bars.

https://www.crumblycookie.net/2008/03/02/raspberry-bars/

Agree with plllog regarding brownies!👍🏻

Sorry, one more I just thought of from my mom. Lots of people have a version of this, but they truly are so good…and easy!

Killer Toffee Bars

2 sticks salted butter, room temp.
1 cup packed golden brown sugar
1 egg, room temp.
1/2 tsp. vanilla
1 cup flour
1/4 tsp. salt
6 plain chocolate Hershey bars (or chocolate of choice)
1/2 cup chopped walnuts or pecans (I like to toast them)

Preheat oven to 325.
Sift together flour and salt. Cream butter with sugar. Add egg and vanilla and beat well. Add flour/salt and mix well. Spread on jelly roll pan (about 10 X 15 X 1). Batter will seem skimpy, but will bake up. Bake for about 20-25 minutes. Remove from oven and immediately place Hershey bars on top. Let sit about 10 minutes or until chocolate melts (Hershey bars will maintain shape and not appear melted, but they are). Spread chocolate evenly over bars and sprinkle walnuts or pecans over top. Let cool slightly and cut into bars while still barely warm.

It's been awhile, but 3 come to mind...

I used to make crumble bar cookies with a sugar cookie dough base and fruit jam mixed with some lemon or lime juice for tang. I also used to make those bars made with crushed graham crackers, condensed milk, chocolate chips and coconut - Magic Cookie Bars.

Then there's these - from one of my vintage cookbooks - they are very much like toffee candy:

Toffee Bars

1 c. sugar (Brown, or white mixed w/ 1 T molasses)

1 cup butter

2 c. flour

1/4 tsp. salt

1-2 tsp. vanilla

1 c. chocolate chips

1 c. chopped nuts

1/2 c. raisins (optional)

Blend all ingredients well.

Press into 10"X15' jelly roll pan.

Bake 18-25 minutes @ 350F (until golden brown).

Cut while hot.

Remove from pan when cool.

IIRC, 1 cup of butter made it too greasy, so I reduced the amount by a couple of Tbs.

I have a number of saved crumble bar recipes, I think this is the one I used, but without the oats, and I cheated with a sugar cooky mix:

Raspberry Crumble Cakes

1 cup butter, at room temperature

1/2 cup sifted confectioners' sugar

2 cups flour

1/2 teaspoon salt

1/2 cup rolled oats

1/2 cup chopped walnuts

3/4 cup raspberry jam

Step 1

Heat the oven to 375° F. Grease a 9-inch square pan with butter or cooking spray.

Step 2

In a mixing bowl, beat the butter and sugar until they're well blended. Add the flour and salt and beat just until the dough forms clumps. Don't overmix. Lightly flour your hands, then place the dough on a piece of waxed paper and squeeze it into a ball (the warmth of your hands will soften the dough enough to hold it together).

Step 3

Divide the dough into thirds. Crumble one third into a bowl and set it aside. Press the remaining 2 thirds evenly into the greased pan using the back of a spoon to smooth the surface. Bake it on the center oven rack until the edges are lightly golden, about 10 minutes.

Step 4

Set the pan on a wire rack. While the shortbread cools, mix the oats and nuts into the reserved dough with your fingers until the mixture is crumbly.

Step 5

Spread the raspberry jam on the cooled shortbread (it's okay if it's still warm), then evenly cover the jam with the crumb topping. Bake the bars until the topping is golden brown, about 24 minutes, then return the pan to the wire rack. While the shortbread is still slightly warm, cut it into 16 squares, then cut each square in half diagonally. Once the triangles cool completely (they are very fragile while warm), lift them from the pan with a spatula. Makes about 2 1/2 dozen.

Carol, we were in sync regarding the toffee bars and raspberry!😉

Neiman Marcus bars

https://therecipecritic.com/neiman-marcus-bars/#wprm-recipe-container-50267

There are lots of variations of this recipe from maybe 30 years ago, but it is probably the best and most decadent combo and easy to make that I've ever had. Some make the brownie from scratch, some use a mix, some make a caramel sauce from scratch, but for your purposes, I would just use caramels, melted. I love that version. Some have updated it to a salted caramel version:

Caramel stuffed Brownies

Looks like you have a lot of suggestions. Keeping it restricted to a certian kind of cookie makes a lot of sense.

There is a very popular outdoor venue near me that has been in business for decades. They have huge grills and smokers and outdoor equipment, obviously. The will bake these pies in the same place as they do the meat. I would assume it is in one of the barrels used for smoking as opposed to an open grill. But I have to tell you that those pies are just awful! Even if there is no wood, that wood smoke is pervasive and stays in there, lending a very undesirable flavor element to the pie. I dont think most people really like that but many dont think to complain as they see it as just a part of the experience. And, they sell experience along with food. Maybe more experience than the food. It does not make for a nice baked goodie.

Why dont folks just bring it already baked? Sounds like a fun thing to do though.

I don’t have a bar cookie recipe but my favorite cookie these days is a kitchen sink cookie from Panera or the Fresh Market version. The ingredients would probably be awesome in a bar, add a little bacon for the win 💕