Defrost ground venison and add to a large bowl. Add crushed Ritz crackers and French-fried onions to a small food processor, and pulse until crumbly. Whisk eggs in a small bowl, then mix warm water, bullion, and tomato paste in a measuring cup until smooth.
Add crackers, French-fried onions, eggs, tomato paste, Worcestershire sauce, crushed garlic, sea salt, crushed red pepper flakes, black pepper, marjoram, sage, and minced serrano (optional) to the meat mixture.
Gently mix ingredients together just until combined, then cover with plastic wrap and refrigerate for one hour.
Preheat Oven to 350℉
Press the meatloaf mixture into an ungreased 8.5"x4.5" loaf pan and bake for 30 minutes. Remove from the oven and brush the top with 3 tablespoons of honey mustard sauce.
Bake for an additional 15 to 20 minutes, or until the internal temperature reaches 160°F when taken with a meat thermometer. Let meatloaf rest for 10 minutes before slicing and serving.
Notes
Combine the ingredients just until everything is incorporated. Overmixing can make the meatloaf dense and tough.
Allow the meatloaf to rest for at least 10 minutes after removing it from the oven. This helps the juices to redistribute and makes it easier to slice the meatloaf without it falling apart.
Store meatloaf leftovers in an airtight container in the refrigerator for up to 5 days.
Venison meatloaf freezes well when stored in freezer ziplock bags. Freeze for up to 3 months.