Prep sausage meat: Add ground meat, salt, pepper, garlic, paprika, onion, water, and baking soda to a mixing bowl. Use your hands or a meat chopper to mix until combined. Cover and refrigerate for at least 2 hours, or overnight. (essential for the right texture and flavor).

Roast peppers and eggplant: Preheat oven to 400°F (205°C). Cut bell peppers in half and remove seeds and stem. Press flat and place a greased baking sheet. Cut stem from eggplant and cut eggplant in half, lengthwise. Remove some of the center flesh/meat from the eggplant and press, flat side down, onto baking sheet. Roast for 30-40 minutes, or until skins are charred and veggies are tender.

Remove skins, and blend: Cover pan with foil and rest for about 15-20 minutes. Carefully peel the skin from the peppers and eggplant and place flesh into a blender. Add minced garlic, 3 tablespoons olive oil, vinegar, paprika, salt, and a pinch of sugar then blend until smooth.

Cook sauce: Heat 2 tablespoons olive oil in a saucepan over medium heat and add blended mixture. Cook for about 15 minutes, stirring often, until thickened. Taste and add more salt if needed. Allow to cool. Ajvar sauce can be made 1 week ahead.

Form sausages by scooping meat mixture into 2-tablespoons-size balls, then roll each portion into a sausage shape, about 3/4-inch wide and 3-4 inches long. (Should make about 30 sausages).

Cook Sausages: Heat a grill (charcoal grill is most authentic) or cast-iron skillet with a little olive oil, on the stove. Cook over medium-high heat, turning often as they cook, until browned well on all sides, and cooked through (about 7-10 minutes).

Warm Pitas: Cut pitas in half and place them briefly on hot grill next to sausages, then press them on top of the sausages, to warm and soften them from some of the sausage grease.

Serve: Place warm pita on a plate. Add 5-6 sausages, partially inside the pita, and coming out onto the plate, Add chopped onion on top. Serve ajvar sauce and Greek yogurt on the side.