Cut new potatoes into chunks: eights or quarters depending on the individual potato. Halves if they’re really small. Cut onions into one-inch chunks and peel garlic, leaving cloves whole. Toss in bowl with oil, salt, pepper, and cayenne pepper. Spread onto baking sheet with lip and roast at 375 F for 25-30 minutes or until potatoes are exhibiting some browning, tossing once about halfway through.
As root vegetables roast, snap stem end off of green beans and break into 1-inch pieces. Dice red bell pepper into 1/4-inch pieces (small dice). Cut fresh heirloom tomatoes into chunks, or leave whole if using cherry tomatoes (can use mix of different size and different types of tomatoes. As pictured, there are green zebra tomatoes, black cherry tomatoes, and yellow tomatoes (exact varietal uncertain). Toss these vegetables in the same bowl used for the root vegetables with the same spices and another drizzle of oil. When potatoes exhibit brownness from roasting, add these vegetables to the tray and return to the oven for 10-12 minutes.
Slice green onions and basil thinly. Add to tray at conclusion of 10-12 minutes of roasting the beans and the onions, and return to the oven for a final 3-5 minutes.
Serve immediately in the vessel of your choice. Liquid from the tomatoes provides a stew-like image if served in a casserole dish (as pictured above).